Fix tab content view recreation

[winddpan]

This PR intent to prevent tab content view recreation. Mainly used StateObject to maintain the state and set opacity=0 to keep the view. (And aslo support tab content view lazy loading) Sorry for the many format changes due to SwiftFormat. Also, I made some modifications to the test the view keeping in the demo. If you don't like it, I can submit a new PR with minimal changes.

[onl1ner]

Updated the base branch to release/2.0.0 as it introduces breaking changes.