SwiftUI timeline refactor + TimelineViewState decoupling (#1392)

* swiftUI conversion + scroll to bottom

* remove unused

* back pagination implemented, however when a lot of elements are in the scroll the perfomance diminishes not sure what may be causing it

* scroll adapter solution

* way better

* works but height animation in cells are broken

* code improvement

* everything implemented

* rebase fix

* fix

* doc

* fix test compilation

* code improvement and animation improvement

* code improvement

* code improvements

* tests updated.

* pr comments

* better identifiers

* fix

* some PR comments

* pr comments

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

@@ -228,8 +228,8 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/pointfreeco/xctest-dynamic-overlay",
       "state" : {
-        "revision" : "245d527002f29c5a616c5b7131f6a50ac7f41cbf",
-        "version" : "0.8.6"
+        "revision" : "50843cbb8551db836adec2290bb4bc6bac5c1865",
+        "version" : "0.9.0"
       }
     }
   ],