Discard button for files

[ThomasAunvik]

Description of the Change

Buttons that discards edited files, returning to the previous state, depending on the branch.

Alternate Designs

Right click file, press discard, only discards one file, not meta files from cs files.

Benefits

Discards files when you press the button, can press All then Discard to discard all items.

[ThomasAunvik]

Third commit was cause i created a branch from the first branch, unfortunately, i hope that wont ruin #779.

[ThomasAunvik]

Fixed merge conflicts.

[StanleyGoldman]

Crazy late decision here. 😿
Thanks for the contribution.

We ended up adding a context menu to discard changes.
I'm not sure how much a broader discard function is needed.
Hopefully I can get some product person to help eventually and do that research.

I am going to close this until then.