- legacy Style and ThemePalette removed
- moved and deduplicated font definitions into `Theme` (unrelated to a
color palette)
- `Style.current.foo` -> `Theme.foo`
- `Style.current.fooColor` -> `Theme.palette.fooColor`
- upgrade the imports to 5.15
- removed some mode dead components
Fixes#16514
Moved Message component & dependencies to shared
for usage import shared.views.chat 1.0 and accordingly
import shared.controls/panels.chat 1.0
Closes#3927