Fixes all our Go file imports to match the preferred spec that we've _mostly_ been using. For example:
```
import (
"context"
"time"
"github.com/prometheus/client_golang/prometheus"
"golang.org/x/xerrors"
"gopkg.in/natefinch/lumberjack.v2"
"cdr.dev/slog/v3"
"github.com/coder/coder/v2/codersdk/agentsdk"
"github.com/coder/serpent"
)
```
3 groups: standard library, 3rd partly libs, Coder libs.
This PR makes the change across the codebase. The PR in the stack above modifies our formatting to maintain this state of affairs, and is a separate PR so it's possible to review that one in detail.
Adds a new hidden subcommand `coder connect exists <hostname>` that checks if the name exists via Coder Connect. This will be used in SSH config to match only if Coder Connect is unavailable for the hostname in question, so that the SSH client will directly dial the workspace over an existing Coder Connect tunnel.
Also refactors the way we inject a test DNS resolver into the lookup functions so that we can test from outside the `workspacesdk` package.
Spike Curtis