- 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
- fix a refactoring bug in the stores
- disable the context menu since it's not really usefull and we're still
missing like a dozen of stores needed for MessageView anyway