identity: hack flag to skip handle resolution

[bnewbold]

Motivation here is to slash DNS lookups as part of cached DID resolution. As noted in the doc comment, we should loop back around and update the "Directory" interface/API to support this usecase better.

To actually deploy this in discover, we should:

• confirm that we don't actually use handle resolution anywhere in discover. this will always return DID lookups with "invalid handle"
• configure the redis directory "invalid handle TTL" to have the same duration as "hit" TTL
• set this flag to "true" on the inner/wrapped base directory

This will only impact the "resolve identity by DID" path, not any "resolve identity by handle" paths.