Decouple dependency check from updating mods

[Trial97]

Added a button to check for updates and missing dependencies.
And kept the original button just to update the mods.
fixes #1745
fixes #1814

[getchoo]

i don't see any reason why this needs to wait til 8.1. works as intended in my testing

[Trial97]

I added most of my new PRs to that milestone so I do not slow down the release of 8.0

[TheKodeToad]

I don't like this implementation, because there will be too many buttons :catquake:

[Trial97]

I'm okay with removing this from milestone in favor of #1768 or #1796

[Trial97]

I don't like this implementation, because there will be too many buttons :catquake:

Then you will love what I did to it now (you have fewer visible buttons)

[Madis0]

Should dependencies even be conceptually linked to updates?

As a user, I would maybe assume to find it in the mod addition window instead. For example, I pick a couple mods and there is a button to pick the mods' dependencies for me as well. Though that would not cover existing instance use cases so I'm not fully sure.

Edit: considering 8.0 already does kind of what I suggested (without showing dependencies as I pick mods), then that use case is already covered and this PR's menu can be added for existing instance use cases, indeed.

[Trial97]

It is linked to updates because you can have missing dependencies and you will want to check that (by other means than downloading all mods again through the mod download dialog).
With this PR though the default button will only update(without deps) and there will be a submenu for the dependency check.

[Desoroxxx]

Should dependencies even be conceptually linked to updates?

Mods can add new dependencies with updates.