Refactor Rust timeline identifiers into our own.

[pixlwave]

In preparation for swiping media in the room screen, this PR replaces all the uses of Rust's EventOrTransactionId and TimelineUniqueId with our own local versions as it seems silly to keep importing the SDK into UI layers just to identify things.

Broken into 2 commits, one for each refactor so it should be easier to review.

[github-actions]

	Warnings
⚠️	You seem to have made changes to views. Please consider adding screenshots.

Generated by 🚫 Danger Swift against e4f1329

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

Attention: Patch coverage is 76.52174% with 27 lines in your changes missing coverage. Please review.

Project coverage is 77.53%. Comparing base (10d3925) to head (e4f1329).
Report is 3 commits behind head on develop.

✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...ces/Services/Timeline/TimelineItemIdentifier.swift	48.57%	18 Missing ⚠️
...meline/TimelineController/TimelineController.swift	0.00%	3 Missing ⚠️
...w/TimelineViews/ImageMediaEventsTimelineView.swift	50.00%	1 Missing ⚠️
...Screens/Timeline/TimelineTableViewController.swift	85.71%	1 Missing ⚠️
...View/TimelineItemViews/ImageRoomTimelineView.swift	50.00%	1 Missing ⚠️
...ervices/Room/RoomSummary/RoomSummaryProvider.swift	0.00%	1 Missing ⚠️
...s/Timeline/Fixtures/RoomTimelineItemFixtures.swift	50.00%	1 Missing ⚠️
.../Items/Virtual/TimelineStartRoomTimelineItem.swift	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3731      +/-   ##
===========================================
- Coverage    77.58%   77.53%   -0.05%     
===========================================
  Files          797      797              
  Lines        69319    69329      +10     
===========================================
- Hits         53782    53757      -25     
- Misses       15537    15572      +35     

Flag	Coverage Δ
unittests	70.30% <76.52%> (-0.05%)	⬇️

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[Velin92]

Couldn't we use a typealias of String with some methods on top, instead of defining a struct with a single value?