doc: move development sections to standalone file

README.md

 * [Android](https://play.google.com/store/apps/details?id=org.jitsi.meet)
 * [iOS](https://itunes.apple.com/us/app/jitsi-meet/id1165103905)
 
-## Building the sources
+## Development
 
-Node.js >= 10 and npm >= 6 are required.
-
-On Debian/Ubuntu systems, the required packages can be installed with:
-```
-sudo apt-get install npm nodejs
-cd jitsi-meet
-npm install
-```
-
-To build the Jitsi Meet application, just type
-```
-make
-```
-
-### Working with the library sources (lib-jitsi-meet)
-
-By default the library is build from its git repository sources. The default dependency path in package.json is :
-```json
-"lib-jitsi-meet": "jitsi/lib-jitsi-meet",
-```
-
-To work with local copy you must change the path to:
-```json
-"lib-jitsi-meet": "file:///Users/name/local-lib-jitsi-meet-copy",
-```
-
-To make the project you must force it to take the sources as 'npm update':
-```
-npm install lib-jitsi-meet --force && make
-```
-
-Or if you are making only changes to the library:
-```
-npm install lib-jitsi-meet --force && make deploy-lib-jitsi-meet
-```
-
-Alternative way is to use [npm link](https://docs.npmjs.com/cli/link).
-It allows to link `lib-jitsi-meet` dependency to local source in few steps:
-
-```bash
-cd lib-jitsi-meet
-
-#### create global symlink for lib-jitsi-meet package
-npm link
-
-cd ../jitsi-meet
-
-#### create symlink from the local node_modules folder to the global lib-jitsi-meet symlink
-npm link lib-jitsi-meet
-```
-
- After changes in local `lib-jitsi-meet` repository, you can rebuild it with `npm run install` and your `jitsi-meet` repository will use that modified library.
-Note: when using node version 4.x, the make file of jitsi-meet do npm update which will delete the link. It is no longer the case with version 6.x.
-
-If you do not want to use local repository anymore you should run
-```bash
-cd jitsi-meet
-npm unlink lib-jitsi-meet
-npm install
-```
-### Running with webpack-dev-server for development
-
-Use it at the CLI, type
-```
-make dev
-```
-
-By default the backend deployment used is `beta.meet.jit.si`. You can point the Jitsi-Meet app at a different backend by using a proxy server. To do this, set the WEBPACK_DEV_SERVER_PROXY_TARGET variable:
-```
-export WEBPACK_DEV_SERVER_PROXY_TARGET=https://your-example-server.com
-make dev
-```
-
-The app should be running at https://localhost:8080/
+For web development see [here](doc/development.md), and for mobile see [here](doc/mobile.md).
 
 ## Contributing
 
 The [meet.jit.si](https://meet.jit.si) service is maintained by the Jitsi team
 at [8x8](https://8x8.com).
 
-## Mobile app
-Jitsi Meet is also available as a React Native app for Android and iOS.
-Instructions on how to build it can be found [here](doc/mobile.md).
-
 ## Acknowledgements
 
 Jitsi Meet started out as a sample conferencing application using Jitsi Videobridge. It was originally developed by ESTOS' developer Philipp Hancke who then contributed it to the community where development continues with joint forces!

doc/development.md

+# Developing Jitsi Meet
+
+## Building the sources
+
+Node.js >= 10 and npm >= 6 are required.
+
+On Debian/Ubuntu systems, the required packages can be installed with:
+```
+sudo apt-get install npm nodejs
+cd jitsi-meet
+npm install
+```
+
+To build the Jitsi Meet application, just type
+```
+make
+```
+
+### Working with the library sources (lib-jitsi-meet)
+
+By default the library is build from its git repository sources. The default dependency path in package.json is :
+```json
+"lib-jitsi-meet": "jitsi/lib-jitsi-meet",
+```
+
+To work with local copy you must change the path to:
+```json
+"lib-jitsi-meet": "file:///Users/name/local-lib-jitsi-meet-copy",
+```
+
+To make the project you must force it to take the sources as 'npm update':
+```
+npm install lib-jitsi-meet --force && make
+```
+
+Or if you are making only changes to the library:
+```
+npm install lib-jitsi-meet --force && make deploy-lib-jitsi-meet
+```
+
+Alternative way is to use [npm link](https://docs.npmjs.com/cli/link).
+It allows to link `lib-jitsi-meet` dependency to local source in few steps:
+
+```bash
+cd lib-jitsi-meet
+
+#### create global symlink for lib-jitsi-meet package
+npm link
+
+cd ../jitsi-meet
+
+#### create symlink from the local node_modules folder to the global lib-jitsi-meet symlink
+npm link lib-jitsi-meet
+```
+
+ After changes in local `lib-jitsi-meet` repository, you can rebuild it with `npm run install` and your `jitsi-meet` repository will use that modified library.
+Note: when using node version 4.x, the make file of jitsi-meet do npm update which will delete the link. It is no longer the case with version 6.x.
+
+If you do not want to use local repository anymore you should run
+```bash
+cd jitsi-meet
+npm unlink lib-jitsi-meet
+npm install
+```
+### Running with webpack-dev-server for development
+
+Use it at the CLI, type
+```
+make dev
+```
+
+By default the backend deployment used is `beta.meet.jit.si`. You can point the Jitsi-Meet app at a different backend by using a proxy server. To do this, set the WEBPACK_DEV_SERVER_PROXY_TARGET variable:
+```
+export WEBPACK_DEV_SERVER_PROXY_TARGET=https://your-example-server.com
+make dev
+```
+
+The app should be running at https://localhost:8080/