Forces browser colorscheme based on BookStack color scheme, via
'color-scheme' css property.
Sets proper dark mode colors for some previously missed areas like
templates and attachment control buttons.
Also fixed search bar icon position for some search inputs.
- Primarily moved and re-organised view files.
- Included readme within views to document the convention.
- Fixed some issues with page field select list in previous commit.
- Tweaked some route names while going through.
- Split some views out further.
Closes#2805
