feat(avatar) add ability to customize Gravatar base URL

Also, default to libravatar.

Closes: https://github.com/jitsi/jitsi-meet/issues/4927

config.js

     // Document should be focused for this option to work
     // enableAutomaticUrlCopy: false,
 
+    // Base URL for a Gravatar-compatible service. Defaults to libravatar.
+    // gravatarBaseURL: 'https://seccdn.libravatar.org/avatar/';
+
     // Stats
     //
 

package-lock.json

       }
     },
     "@jitsi/js-utils": {
-      "version": "1.0.2",
-      "resolved": "https://registry.npmjs.org/@jitsi/js-utils/-/js-utils-1.0.2.tgz",
-      "integrity": "sha512-ls+X9tn9EemUQwPEBr7Z0UD4sjRtwcu1Bh4MUo0Hv4arp0KVzcCYCW+mofsvuZvHg8xJX12LLNVgUKi1X5XTGg==",
+      "version": "1.0.3",
+      "resolved": "https://registry.npmjs.org/@jitsi/js-utils/-/js-utils-1.0.3.tgz",
+      "integrity": "sha512-m6mZz7R716mHP21lTKQffyM0nNFu3Fe/EHCaOVLFY/vdPsaUl9DhypJqtPIYzRUfPnmnugdaxcxrUeSZQXQzVA==",
       "requires": {
         "bowser": "2.7.0",
         "js-md5": "0.7.3"
         "webrtc-adapter": "7.5.0"
       },
       "dependencies": {
+        "@jitsi/js-utils": {
+          "version": "1.0.2",
+          "resolved": "https://registry.npmjs.org/@jitsi/js-utils/-/js-utils-1.0.2.tgz",
+          "integrity": "sha512-ls+X9tn9EemUQwPEBr7Z0UD4sjRtwcu1Bh4MUo0Hv4arp0KVzcCYCW+mofsvuZvHg8xJX12LLNVgUKi1X5XTGg==",
+          "requires": {
+            "bowser": "2.7.0",
+            "js-md5": "0.7.3"
+          }
+        },
+        "js-md5": {
+          "version": "0.7.3",
+          "resolved": "https://registry.npmjs.org/js-md5/-/js-md5-0.7.3.tgz",
+          "integrity": "sha512-ZC41vPSTLKGwIRjqDh8DfXoCrdQIyBgspJVPXHBGu4nZlAEvG3nf+jO9avM9RmLiGakg7vz974ms99nEV0tmTQ=="
+        },
         "uuid": {
           "version": "8.1.0",
           "resolved": "https://registry.npmjs.org/uuid/-/uuid-8.1.0.tgz",

package.json

     "@atlaskit/theme": "7.0.2",
     "@atlaskit/toggle": "5.0.14",
     "@atlaskit/tooltip": "12.1.13",
-    "@jitsi/js-utils": "1.0.2",
+    "@jitsi/js-utils": "1.0.3",
     "@microsoft/microsoft-graph-client": "1.1.0",
     "@react-native-community/async-storage": "1.3.4",
     "@react-native-community/google-signin": "3.0.1",

react/features/base/participants/functions.js

 // @flow
 
 import { getGravatarURL } from '@jitsi/js-utils/avatar';
+import type { Store } from 'redux';
 
 import { JitsiParticipantConnectionStatus } from '../lib-jitsi-meet';
 import { MEDIA_TYPE, shouldRenderVideoTrack } from '../media';
  */
 const AVATAR_QUEUE = [];
 const AVATAR_CHECKED_URLS = new Map();
-/* eslint-disable arrow-body-style */
+/* eslint-disable arrow-body-style, no-unused-vars */
 const AVATAR_CHECKER_FUNCTIONS = [
-    participant => {
+    (participant, _) => {
         return participant && participant.isJigasi ? JIGASI_PARTICIPANT_ICON : null;
     },
-    participant => {
+    (participant, _) => {
         return participant && participant.avatarURL ? participant.avatarURL : null;
     },
-    participant => {
-        return participant && participant.email ? getGravatarURL(participant.email) : null;
+    (participant, store) => {
+        if (participant && participant.email) {
+            return getGravatarURL(participant.email, store.getState()['features/base/config'].gravatarBaseURL);
+        }
+
+        return null;
     }
 ];
-/* eslint-enable arrow-body-style */
+/* eslint-enable arrow-body-style, no-unused-vars */
 
 /**
  * Resolves the first loadable avatar URL for a participant.
  *
  * @param {Object} participant - The participant to resolve avatars for.
+ * @param {Store} store - Redux store.
  * @returns {Promise}
  */
-export function getFirstLoadableAvatarUrl(participant: Object) {
+export function getFirstLoadableAvatarUrl(participant: Object, store: Store<any, any>) {
     const deferred = createDeferred();
     const fullPromise = deferred.promise
-        .then(() => _getFirstLoadableAvatarUrl(participant))
+        .then(() => _getFirstLoadableAvatarUrl(participant, store))
         .then(src => {
 
             if (AVATAR_QUEUE.length) {
  * Resolves the first loadable avatar URL for a participant.
  *
  * @param {Object} participant - The participant to resolve avatars for.
+ * @param {Store} store - Redux store.
  * @returns {?string}
  */
-async function _getFirstLoadableAvatarUrl(participant) {
+async function _getFirstLoadableAvatarUrl(participant, store) {
     for (let i = 0; i < AVATAR_CHECKER_FUNCTIONS.length; i++) {
-        const url = AVATAR_CHECKER_FUNCTIONS[i](participant);
+        const url = AVATAR_CHECKER_FUNCTIONS[i](participant, store);
 
         if (url) {
             if (AVATAR_CHECKED_URLS.has(url)) {

react/features/base/participants/middleware.js

  * @private
  * @returns {Object} The value returned by {@code next(action)}.
  */
-function _participantJoinedOrUpdated({ dispatch, getState }, next, action) {
+function _participantJoinedOrUpdated(store, next, action) {
+    const { dispatch, getState } = store;
     const { participant: { avatarURL, e2eeEnabled, email, id, local, name, raisedHand } } = action;
 
     // Send an external update of the local participant's raised hand state
         const participantId = !id && local ? getLocalParticipant(getState()).id : id;
         const updatedParticipant = getParticipantById(getState(), participantId);
 
-        getFirstLoadableAvatarUrl(updatedParticipant)
+        getFirstLoadableAvatarUrl(updatedParticipant, store)
             .then(url => {
                 dispatch(setLoadableAvatarUrl(participantId, url));
             });

react/features/lobby/middleware.js

  * @param {Object} participant - The knocking participant.
  * @returns {void}
  */
-function _findLoadableAvatarForKnockingParticipant({ dispatch, getState }, { id }) {
+function _findLoadableAvatarForKnockingParticipant(store, { id }) {
+    const { dispatch, getState } = store;
     const updatedParticipant = getState()['features/lobby'].knockingParticipants.find(p => p.id === id);
     const { disableThirdPartyRequests } = getState()['features/base/config'];
 
     if (!disableThirdPartyRequests && updatedParticipant && !updatedParticipant.loadableAvatarUrl) {
-        getFirstLoadableAvatarUrl(updatedParticipant).then(loadableAvatarUrl => {
+        getFirstLoadableAvatarUrl(updatedParticipant, store).then(loadableAvatarUrl => {
             if (loadableAvatarUrl) {
                 dispatch(participantIsKnockingOrUpdated({
                     loadableAvatarUrl,