Add Modpack-page to instances that were created from files

[Trial97]

Parrent PR: #1405
should fix: #1394 (comment)
From that comment looks like I did not fix the original issue just extended the functionality of the managed packs(downloaded through prism from modrinth/curseforge)
This PR aims to have a page for local packs (imported from files).
This only works with CurseForge and Modrinth packs.

How to test:

download a modrinth pack( an older version)
install it using the mrpack file
download a newer version of the pack(outside of prism)
click edit instance on the created instance
you should have a similar page as when that pack would be downloaded through prism
entering that page you will be greeted with:
    the pack name(the name of the instance)
    a big button with upload from file
    a changelog that explains this is a local pack and can only be updated through respective format
click on the upload from file
select the new version
profit

Also fixes #1731
fixes #1813

[Trial97]

This PR and #1727 are self-exclusive once one is accepted the other one should be closed.

[DioEgizio]

i personally prefer this approach over the other one but idk what the other mantainers think

[Trial97]

Regarding the ui: the button is gigantic but I have zero talent for UX can you suggest an alternative(a mockup)
Also regarding on a way to link to a modrinth/curseforge pack a solution can be found in: hhttps://github.com//pull/1414 where once you import a file we try to detect if is a curseforge/modrinth pack and if yes just make it one(right now works only for modrinth)

[github-actions]

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