DM Details View (#744)

* Basic implementation completed but it requires some bug fixing and polishing (+4 squashed commits)
Squashed commits:
[43f0064e] now the content of the room details reflects the expected dm details content when the conditions are met
[fe6f2b5e] replaced existing headers with a composable and reusable HeaderView
[3c00120a] now the members are fetched every time the room is opened
[421d539b] refactored the members fetching to be immediate in case the room could be a direct chat

* polished the code and fixed some bugs that prevented the updated state of the members to be displayed in the room details view (+1 squashed commit)
Squashed commits:
[6bf98473] fix for the button not being destructive in room details screen

* removed copy button and updated copy

* moved a file and renamed header view

* addressed all PR comments

* sdk bump

* UI tests

* unit tests

* changelog

* updated mocks

* removed a duplicated signature in a mock

ElementX.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved

@@ -163,7 +163,7 @@
     {
       "identity" : "swift-snapshot-testing",
       "kind" : "remoteSourceControl",
-      "location" : "https://github.com/pointfreeco/swift-snapshot-testing",
+      "location" : "https://github.com/pointfreeco/swift-snapshot-testing.git",
       "state" : {
         "revision" : "cef5b3f6f11781dd4591bdd1dd0a3d22bd609334",
         "version" : "1.11.0"