Feature: add room threads list (#6575)

Add threads list screen for rooms:

- Add `ThreadsListService` to subscribe to thread changes in the room.
- Create `ThreadsListView` and its associated node a presenters (the UI may change).
- Add a menu icon in the room screen to open it.

This is still pending info about unread threads, so several UI components related to it will be hidden.

* Add feature flag and use it to hide the access to this new screen

---------

Co-authored-by: ElementBot <android@element.io>

tests/uitests/src/test/snapshots/images/features.messages.impl.threads.list_ThreadListItemRow_Day_0_en.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:c523f3a502600b837c07ecd5804831da2d9aba5a74886b7001affbb90169112a
+size 12455

tests/uitests/src/test/snapshots/images/features.messages.impl.threads.list_ThreadListItemRow_Night_0_en.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:528c2f3183a153b9129606806fc457265819ececd71cf5021d1d843970c0b774
+size 12366

tests/uitests/src/test/snapshots/images/features.messages.impl.threads.list_ThreadsListView_Day_0_en.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:4c02999b2d0eba92f1e9b1f5fac52bcff303401f177459d1a439b7db906e5c2a
+size 64622

tests/uitests/src/test/snapshots/images/features.messages.impl.threads.list_ThreadsListView_Night_0_en.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:a7f6b64bfe0b47546a009efe23060ba091adbad32288ce546cb3b030d7a9ec88
+size 66177

tests/uitests/src/test/snapshots/images/features.messages.impl.topbars_MessagesViewTopBar_Day_0_en.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:3136c95bc9134eba4cfdfe8d552473a54287c356bd3895291b9cd4ec11969d9c
-size 52706
+oid sha256:e26887bd81e10726414e1833029b4b51e22e534684a230777ca50f86024af994
+size 56430

tests/uitests/src/test/snapshots/images/features.messages.impl.topbars_MessagesViewTopBar_Night_0_en.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:6770e720477c2547f593c626cfe3bdafb9b7c78d0b66e910fb9eb1163730045f
-size 51707
+oid sha256:ce44cf850169736008a3f3fc21a2be4fb044badfae631b0284ce379b325879df
+size 55533