Refactor outputs.rs after iced 14 migration

[MalpenZibo]

The scaling issue on new surfaces seems resolved in iced 14.

For this reason, PR #456 can be merged, and we can simplify the outputs.rs file a lot.

We don't have to keep the menu surface always open, but we can open it only when we need it.

We just have to respect the user preferences on which monitor to use for ashell and provide a fallback on the "active" monitor in case the desired ones are not available

[MalpenZibo]

@romanstingler, if this can interest you, I just added it to the roadmap

[romanstingler]

Thanks, I will have a look in the evening

[MalpenZibo]

@romanstingler Have you already started to see this? Because recently I had a "lot" of free time, so I began to check this, and this is the result #656.

Sorry if you already started the work. In case we could discuss our approach and come up with a common solution

[romanstingler]

@MalpenZibo hey, sorry, last few weeks I was a bit busy with other stuff.
That is fine, I am not working on anything UI / UI backend related (except if it is tied to a module output).

[romanstingler]

I guess we can close this after #656

[MalpenZibo]

yep!