rn,flags: add "toolbox.alwaysVisible" flag

react/features/base/flags/constants.js

  */
 export const TILE_VIEW_ENABLED = 'tile-view.enabled';
 
+/**
+ * Flag indicating if the toolbox should be always be visible
+ * Default: disabled (false).
+ */
+export const TOOLBOX_ALWAYS_VISIBLE = 'toolbox.alwaysVisible';
+
 /**
  * Flag indicating if the welcome page should be enabled.
  * Default: disabled (false).

react/features/toolbox/functions.native.js

 // @flow
 
+import { TOOLBOX_ALWAYS_VISIBLE, getFeatureFlag } from '../base/flags';
 import { toState } from '../base/redux';
 
 /**
     const state = toState(stateful);
     const { alwaysVisible, enabled, visible } = state['features/toolbox'];
     const { length: participantCount } = state['features/base/participants'];
+    const flag = getFeatureFlag(state, TOOLBOX_ALWAYS_VISIBLE, false);
 
-    return enabled && (alwaysVisible || visible || participantCount === 1);
+    return enabled && (alwaysVisible || visible || participantCount === 1 || flag);
 }