Allow replacement by conflicting modules

[HebaruSan]

Problem

If a module conflicts with its replaced_by module, clicking the Replace checkbox reports the conflict and blocks installation in GUI as if we were going to install both of them:

Noted as part of KSP-CKAN/NetKAN#7027.

Cause

This call throws because it tries to resolve relationships with both conflicting modules installed:

CKAN/GUI/MainModList.cs

Lines 689 to 702 in 6b4cd14

	while (!handled_all_too_many_provides)
	{
	//Can't await in catch clause - doesn't seem to work in mono. Hence this flag
	TooManyModsProvideKraken kraken;
	try
	{
	new RelationshipResolver(
	modules_to_install,
	null,
	RelationshipResolver.DependsOnlyOpts(),
	registry, version);
	handled_all_too_many_provides = true;
	continue;
	}

That null value was set in #2579, and is the parameter for modules that will be removed; previously we passed modules_to_remove, which caused a different exception to be thrown if you removed a module that other modules depend on.

Changes

Now the reverse dependency logic happens first, and adds the reverse dependencies to modules_to_remove. This then allows us to pass modules_to_remove to the RelationshipResolver of the provides loop, since removing the reverse dependencies will prevent an inconsistency from being created.

modules_to_remove is then also passed to the final RelationshipResolver which previously recalculated it independently based on the change set, to save a few extra operations.