Make VIES validation optional

Adding MR as patch file as well, for composer-based patching workflows.

I am at DrupalCon Lille and will give this one a try.

I reviewed the MR by checking the coding and testing the added feature.
Tested before and after applying the MR.
Everything works as described.

Having a configuration option should also have the correct config schema. So setting back to needs work.

Added the schema and committed.

Automatically closed - issue fixed for 2 weeks with no activity.