Share extension (#3506)

* Setup simple share extension

* Switch the app url scheme to be the full bundle identifier

* Setup a share extension that show a SwiftUI view, uses rust tracing and redirects to the hosting aplication

* Move media as json through the custom scheme into the main app and deep link into the media upload preview screen

* Fix message forwarding and global search screen room summary provider filtering.

* Tweak the message forwarding and global search screen designs.

* Add a room selection screen to use after receiving a share request from the share extension

* Fix share extension entitlements

* Share the temporary directory between the main app and the extensions; rename the caches one.

* Remove the no longer needed notification avatar flipping fix.

* Extract the placeholder avatar image generator from the NSE

* Nest `AvatarSize` within the new `Avatars` enum

* Donate an `INSendMessageIntent` to the system every time we send a message so they appear as share suggestions

* Support suggestions in the share extension itself

* Improve sharing animations and fix presentation when room already on the stack

* Clear all routes when sharing without a preselected room.

* Fix broken unit tests

* Various initial tweaks following code review.

* Correctly clean up and dismiss the share extension for all paths.

* Move the share extension path to a constants enum

* Rename UserSessionFlowCoordinator specific share extension states and events

* Add UserSession and Room flow coordinator share route tests

* Tweak the share extension logic.

ElementX/SupportingFiles/Info.plist

@@ -54,7 +54,7 @@
 			<string>Application</string>
 			<key>CFBundleURLSchemes</key>
 			<array>
-				<string>io.element</string>
+				<string>$(BASE_BUNDLE_IDENTIFIER)</string>
 			</array>
 		</dict>
 	</array>

ElementX/SupportingFiles/target.yml

@@ -66,7 +66,7 @@ targets:
             CFBundleTypeRole: Editor,
             CFBundleURLName: "Application",
             CFBundleURLSchemes: [
-              io.element
+              $(BASE_BUNDLE_IDENTIFIER)
             ]
           }
         ]
@@ -189,6 +189,7 @@ targets:
 
     dependencies:
     - target: NSE
+    - target: ShareExtension
     # not used yet
     # - target: NCE
     - package: MatrixRustSDK