Update metalinter, fix a few lint warnings and replace deprecated linters.
`deadcode`, `structcheck` and `varcheck` are abandoned and now replaced by [`unused`][1].
Since 1.19, `go fmt` reformats godocs according to https://go.dev/doc/comment. I've done a bulk-reformatting of the codebase to keep the linter happy. Backporting is mostly harmless (the exception being `lib/services/role_test.go`, that for some reason breaks the _old_ linter using the new format).
[1]: https://golangci-lint.run/usage/linters/
* Bump golangci-lint version
* Replace abandoned linters
* Fix bodyclose on lib/auth/github.com
* Fix bodyclose on lib/kube/proxy/streamproto/proto_test.go
* Fix bodyclose on lib/srv/alpnproxy/proxy_test.go
* Fix bodyclose on lib/web/conn_upgrade_test.go
* Silence staticcheck on lib/kube/proxy/forwarder_test.go
* Silence staticcheck on lib/utils/certs_test.go
* Address BuildNameToCertificate deprecation warnings
* Run `go fmt ./...`
* Run `go fmt ./...` on api/
* Ignore formatting in role_test.go
* Remove redundant initializers in lib/srv/uacc/
* Update e/
This adds proxy peering support. A configurable setting that allows for agents
to connect to a subset of proxies and be reachable through any proxy in the
cluster. This is achieved by creating grpc connections between each proxy
server. Client connections can then be passed between proxies to the desired
agent.
Alan Parra