Previously, public referred to gRPC services that are both exposed on
the dedicated gRPC port and have their definitions in the proto-public
directory (so were considered usable by 3rd parties). Whereas private
referred to services on the multiplexed server port that are only usable
by agents and other servers.
Now, we're splitting these definitions, such that external/internal
refers to the port and public/private refers to whether they can be used
by 3rd parties.
This is necessary because the peering replication API needs to be
exposed on the dedicated port, but is not (yet) suitable for use by 3rd
parties.
Introduces two new public gRPC endpoints (`Login` and `Logout`) and
includes refactoring of the equivalent net/rpc endpoints to enable the
majority of logic to be reused (i.e. by extracting the `Binder` and
`TokenWriter` types).
This contains the OSS portions of the following enterprise commits:
- 75fcdbfcfa6af21d7128cb2544829ead0b1df603
- bce14b714151af74a7f0110843d640204082630a
- cc508b70fbf58eda144d9af3d71bd0f483985893
* Implement the ServerDiscovery.WatchServers gRPC endpoint
* Fix the ConnectCA.Sign gRPC endpoints metadata forwarding.
* Unify public gRPC endpoints around the public.TraceID function for request_id logging
Introduces a gRPC endpoint for signing Connect leaf certificates. It's also
the first of the public gRPC endpoints to perform leader-forwarding, so
establishes the pattern of forwarding over the multiplexed internal RPC port.
