UI changes for connected gensets

[DanielMcInnes]

as per gui-v1 commit b9583fd7bee8f1120402ba4697693765c6f06f26

I think most of these are done, except for the text notifications

UI changes for connected gensets
https://github.com/victronenergy/venus/issues/1288

- Remove "Mode" option
- Move "Autostart" and "Manual start" from the autostart menu to the toplevel
- Show GX control (start/stop service) status and error code
- Show genset "Remote start mode" status
- Add text notification and disable the manual control menu items
when "remote start mode" on genset is disabled.

The generator start/stop menu from the main settings menu is unchanged.