Added tab closing when process exists & app closes when no more tabs

[SelfMadeSystem]

Description

• Added tab closing when process exists
• Added app closing when no more tabs open

Type of change

Please tick the relevant option by putting an X inside the bracket

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

(Bit of both I guess)

Checklist:

• My code follows the guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas; tf none of your code is commented. Easy to read anyways.
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• All current GitHub actions pass
• Any dependent changes have been merged and published in downstream modules
• I have checked my code and corrected any misspellings
• I have read the CONTRIBUTING document

[nmcain]

I'm not sure if this would work well with the embdedded view inside pangolin. Can someone test this?

[SelfMadeSystem]

Did someone test this yet?

[larsb24]

@SelfMadeSystem

Did someone test this yet?

Hi, I just pushed a fix for the whole tab situation as the whole app was broken due to dependency changes etc.
If you're fine with it, you could maybe try to fix the conflicts for the PR or I try to copy your changes, since we need to do some refactoring for this repo either way