Refactor: Create ScrollableTextView component

[MichaelAug]

Multiple UI elements have a text area with a vertical scroll bar. This can be refactored into a reusable component to reduce code duplication and improve UI consistency.

Tasks:

1. Create ScrollableTextView component
2. Refactor MsgPopup to use new component
3. Refactor DetailsComponent to use new component

[MichaelAug]

Looks like we could use ratatui's built in Scrollbar widget instead of our custom one. This could simplify scroll_vertical.rs and scroll_horizontal.rs and probably remove scrollbar.rs entirely. Would you like this done?

Here's a comparison of the current scrollbar: And the ratatui built in (default look):

[extrawurst]

I havent looked into the impact of this but i am all for simplifying and using a upstream solution where we can if it does not degrade performance

[MichaelAug]

I havent looked into the impact of this but i am all for simplifying and using a upstream solution where we can if it does not degrade performance

I think swapping the custom scrollbar with the ratatui one shouldn't be too difficult, I'll make a PR so we can test the changes

[MichaelAug]

I've made a small PR to test the scrollbar. You can see the new scrollbar in e.g. tag description or the file list. Looks like a lot of scrollable components don't use VerticalScroll. https://github.com/extrawurst/gitui/pull/2393