* Migrate protobuf generation to Buf
Buf simplifies the generation story and allows us to lean
into other features in the Buf ecosystem, such as dependency
management, linting, breaking change detection, formatting
and remote plugins.
* Format all protobuf files with buf
Also add a CI job to ensure formatting remains consistent
* Add CI job to warn on proto generate diffs
Some files were not regenerated with the latest version
of the protobuf binary. This CI job will ensure we are always
detect if the protobuf files need regenerating.
* Add CI job for linting protobuf files
The [WebSockets spec](https://www.rfc-editor.org/rfc/rfc6455) states
that text messages must be valid UTF-8 encoded strings, which protobuf
messages virtually never are. This now correctly sends the protobuf events
as binary messages.
We change the format to correspond to CloudEvents, as originally intended,
and remove a redundant timestamp and newline.
We also bump the eventlogger to fix a race condition that this code triggers.
Also updates the event receieved to include a timestamp.
Websockets support both JSON and protobuf binary formats.
This can be used by either `wscat` or the new
`vault events subscribe`:
e.g.,
```sh
$ wscat -H "X-Vault-Token: $(vault print token)" --connect ws://127.0.0.1:8200/v1/sys/events/subscribe/abc?json=true
{"event":{"id":"5c5c8c83-bf43-7da5-fe88-fc3cac814b2e", "note":"testing"}, "eventType":"abc", "timestamp":"2023-02-07T18:40:50.598408Z"}
...
```
and
```sh
$ vault events subscribe abc
{"event":{"id":"5c5c8c83-bf43-7da5-fe88-fc3cac814b2e", "note":"testing"}, "eventType":"abc", "timestamp":"2023-02-07T18:40:50.598408Z"}
...
```
Co-authored-by: Tom Proctor <tomhjp@users.noreply.github.com>
