[SECURITY] Create an interceptor for Internal requests

[mmtftr]

Some internal requests such as InternalCreateSignedTx can be abused to generate invalid proofs for disproving the operator. We should be intercepting all "Internal" requests.

For the authentication method, we'd like to have a Bearer header with the token being a secret token unique to each machine.

This token will for now be generated using the hash of the actor secret key.