Bumps the Tailnet and Agent API version 2.3, and creates some extra controls and machinery around these versions.
What happened is that we accidentally shipped two new API features without bumping the version. `ScriptCompleted` on the Agent API in Coder v2.16 and `RefreshResumeToken` on the Tailnet API in Coder v2.15.
Since we can't easily retroactively bump the versions, we'll roll these changes into API version 2.3 along with the new WorkspaceUpdates RPC, which hasn't been released yet. That means there is some ambiguity in Coder v2.15-v2.17 about exactly what methods are supported on the Tailnet and Agent APIs. This isn't great, but hasn't caused us major issues because
1. RefreshResumeToken is considered optional, and clients just log and move on if the RPC isn't supported.
2. Agents basically never get started talking to a Coderd that is older than they are, since the agent binary is normally downloaded from Coderd at workspace start.
Still it's good to get things squared away in terms of versions for SDK users and possible edge cases around client and server versions.
To mitigate against this thing happening again, this PR also:
1. adds a CODEOWNERS for the API proto packages, so I'll review changes
2. defines interface types for different API versions, and has the agent explicitly use a specific version. That way, if you add a new method, and try to use it in the agent without thinking explicitly about versions, it won't compile.
With the protocol controllers stuff, we've sort of already abstracted the Tailnet API such that the interface type strategy won't work, but I'll work on getting the Controller to be version aware, such that it can check the API version it's getting against the controllers it has -- in a later PR.
Drops support for v1 of the tailnet API, which was the original coordination protocol where we only sent node updates, never marked them lost or disconnected.
v2 of the tailnet API went GA for CLI clients in Coder 2.8.0, so clients older than that would stop working.
fixes#10531
Adds a check for `version` on connection to the Agent API websocket endpoint. This is primarily for future-proofing, so that up-level agents get a sensible error if they connect to a back-level Coderd.
It also refactors the location of the `CurrentVersion` variables, to be part of the `proto` packages, since the versions refer to the APIs defined therein.
