…implementation (#55256)

Migrating `AddCustomTemplateModalContent`
 - Removes `__unstableComposite` imports from `@wordpress/components`
 - Adds private `Composite*` exports from `@wordpress/components`
 - Refactors `SuggestionList` and `SuggestionListItem` to use updated `Composite` components

* in progress (+9 squashed commits)
Squashed commits:
[0e51c10685] In progress.
[fdecb78889] new base copy
[0cd4b10502] package lock
[401a7b415a] php lint fixes
[62c4829170] endpoint updates
[8c95d06ba2] fixes and remove unlimited connection
[05d5134c0b] package lock & lint fixes
[9a85abdd68] Working signaling server using wp ajax admin
[f5f13f7d57] Base y-webrtc copied

* Update lib/sync/endpoint.php

Co-authored-by: Anton Vlasenko <43744263+anton-vlasenko@users.noreply.github.com>

* Update lib/sync/endpoint.php

Co-authored-by: Anton Vlasenko <43744263+anton-vlasenko@users.noreply.github.com>

* Update lib/sync/endpoint.php

Co-authored-by: Anton Vlasenko <43744263+anton-vlasenko@users.noreply.github.com>

* Refactor to a class.

* Use fetch instead of XMLHttpRequest.

* Fixed possible race condition and added file access error handling.

* Refactor to createWebRTCConnection.

* Rename unique to subscriber_id. And improve code sending messages.

* Remove use of an hack for multiple messages.

* Use fetch instead of XMLHttpRequest

* Add documentation for the signalling server

* Add signalling server loading back

* Remove hardcoded url from the docs.

* Updated sync readme.

* Fix undefined error on test.

* Update package lock.

* Document the Event stream format

* Update docs for signaling server

* Update lib/experimental/sync/class-gutenberg-http-signaling-server.php

Co-authored-by: André <583546+oandregal@users.noreply.github.com>

* refactor in progress

* tmp

* fix some bugs after refactoring

* Added retry mechanism with error events.

* Document clean_up_old_connections.

* Make parameter order consistent.

* Document remaining parameters.

* Follow y-webrtc room name convention

* Conditionally enable endpoint depending if setting is set or not.

* Remove debug code.

* Fix rebase: remove no longer existing file

* Update docs

---------

Co-authored-by: Anton Vlasenko <43744263+anton-vlasenko@users.noreply.github.com>
Co-authored-by: André Maneiro <583546+oandregal@users.noreply.github.com>

* [Data views]: Update `all templates` page

* feedback part 1

* simple remove action

* Allow actions to use a Modal

* support only list view for first iteration

* remove leftovers since only supporting list view type

* refactor item actions

* fix action item on click callback

* Add block gap support to Quote block.

* Change cite display in front end to match editor styles

* Target only direct descentants