[Feature] "discourages" relationship

[HebaruSan]

Problem

As suggested by @yalov on the Discord, sometimes two mods technically can be installed and work together, but they do mostly the same thing and usually the user would only want one or the other.

For example, KerbalNRAP and UtilityWeight both add parts that can be used to simulate a payload of a specific mass. They can be installed together without crashing KSP, but it would be redundant and unnecessary.

Other examples:

• KER / VOID / BasicOrbit
• Autopilot mods
• WaterLaunchSites / KSCHarbor

Suggestions

This could be handled with a new "discourages" relationship, intended to connote the opposite of "recommends":

identifier: KerbalNRAP
discourages:
  - name: UtilityWeight

This would have the following effects:

• Downgrade a recommendation (checked by default) to a suggestion (unchecked by default) if it is discouraged by any of my installed or installing mods, presumably with a message somewhere
• When selecting discouraged mods on the modlist, show a highlight and a warning that looks similar to a conflict but can be bypassed (the apply changes button isn't disabled)
• A similar warning and/or confirmation prompt if a discouraged mod is pulled in as a dependency

[HebaruSan]

This is similar to #211.