Pass Identifier types over gRPC/db

[orangepizza]

in old version there are few places Authztopb or PbtoAuthz / and then input to db identifier types were discarded and upon re-hydrating it codes made new Identifier with type DNS.
while I think it may better to be sent as uint8 type, two identifierType types with different underlying types would be too confusing so it'll sent as string

kinda part of #7311, first two subtasks

[aarongable]

As noted in #7311, we have two other priorities that are prerequisites before we're fully ready to work on IP Identifier things. While our eventual support for IP addresses might look something like this, it's likely not worth adding this now and then sitting on dead code for a few months. I'm going to close this PR; if you want to be part of implementing our major 2024 goals, reach out on the community forum and I'll be happy to chat about where we could use the help!