Model-specific homescreen layouts

[matejcik]

Currently the homescreen layout is custom written in apps.homescreen. This is becoming more complex as we are adding more different models.

A proposed split would look vaguely like:

• move HomescreenBase to ui.components.common
• move Homescreen, Lockscreen, RecoveryHomescreen to ui.components.tt, quite possibly to a common file homescreen.py
• move ui.header_warning and ui.header_error to ui.components.tt.homescreen (they are not used anywhere else)
• extract appropriate parameters
  • for Homescreen, the list of possible headers should come in as (for now) error_header: str | None, warning_header: str | None. In the future we can pass in something like list[tuple[Level, str]] and the homescreen would decide whether to render everything or only the first/last one.
• provide trezor.ui.layout.show_homescreen(...) and friends