Align enableExperimentalPublicKeyTypes with overrideVerificationMethodTypePolicy

[peacekeeper]

I really like the idea of the enableExperimentalPublicKeyTypes resolution option and invalidPublicKeyType error. We have also defined and implemented something very similar:

• The option overrideVerificationMethodTypePolicy
• The error notAllowedVerificationMethodType

See https://github.com/decentralized-identity/did-spec-extensions/blob/main/error-codes/not-allowed-verification-method-type.md.

This is one of several security-related policies that a resolver can enforce, see here for more: https://github.com/decentralized-identity/did-spec-extensions

I think the only difference is that in our case, individual verification method types (such as Ed25519VerificationKey2018) can be allowed/denied by a resolver, whereas in your case your option is about a group of types (such as "experimental"). It should be possible to harmonize both into a single option.