Recommendation suppression for modpacks

[HebaruSan]

Motivation

Currently, in order to install the exact list of mods in a modpack, the user has to deselect the recommendations of all the mods. It would be nice to be able to skip this step.

It looks like setting suppress_recommendations for each item in the depends list should work, but it doesn't because those items get added as first class members of the changeset, which causes that property to be ignored in the modpack.

A similar thing can happen in a normal changeset; if A and B are in the changeset, and both depend on C but only A has suppress_recommendations set, B's lack of the property will mean that C's recommendations are still shown. That probably frustrates the author of A, especially if they're from KSP-RO.

Changes

• Now suppress_recommendations is obeyed if it is set for any depends relationship in the changeset, even if other mods have the same dependency without that property or if the dependency is in the changeset itself.
  • Since modpacks are included in changesets, this means that depends[].suppress_recommendations in a modpack will now work.
  • It also means that in the above A/B/C scenario, C's recommendations will no longer be shown, which the KSP-RO folks will probably like.
• Now the export modpack screen in GUI has an "Include optional relationships" checkbox that sets suppress_recommendations for every relationship in depends if unchecked, to make it easy to generate such metadata.

Fixes #4145.

[JonnyOThan]

Seems to work!