Allow specifying passability for PartVariants

[Khitiara]

Proposal is to allow different passability for different PartVariants of a part. Example use-case: PorktoberRevolution/ReStocked#959 where the Size1to0ServiceModule is given a docking tunnel variant by the Restock addon, but the docking tunnel variant is not passable with CLS since the overall part is not due to the vanilla bare variant

[mwerle]

Thank you, I'll have to have a look into how this can be achieved.

[mwerle]

The code from this plugin could be useful :
https://github.com/KSPSnark/VariantPersist

We'd still need to add a way to add per-variant CLS rules into the config files though, and apply them whenever a part variant is switched.

Ultimately seems like a fair bit of work to support a single part from another mod.

PS, the specific part in question is actually in ReStockPlus, not ReStock.