allow a wildcard * in disallow_attester_search_for_domains

[tomholub]

Currently, we match domains exactly, eg disallow_attester_search_for_domains: ["example.com"]. I'd like to update this so that value * simply means disallow searching on all.

We don't have to support more complicated patterns like *.domain.com or test.*.domain.com - that's out of scope.

part of #2125