feat: Improve resource preview and first-time experience (#946)

* Improve CLI documentation

* feat: Allow workspace resources to attach multiple agents

This enables a "kubernetes_pod" to attach multiple agents that
could be for multiple services. Each agent is required to have
a unique name, so SSH syntax is:

`coder ssh <workspace>.<agent>`

A resource can have zero agents too, they aren't required.

* Add tree view

* Improve table UI

* feat: Allow workspace resources to attach multiple agents

This enables a "kubernetes_pod" to attach multiple agents that
could be for multiple services. Each agent is required to have
a unique name, so SSH syntax is:

`coder ssh <workspace>.<agent>`

A resource can have zero agents too, they aren't required.

* Rename `tunnel` to `skip-tunnel`

This command was `true` by default, which causes
a confusing user experience.

* Add disclaimer about editing templates

* Add help to template create

* Improve workspace create flow

* Add end-to-end test for config-ssh

* Improve testing of config-ssh

* Fix workspace list

* Fix config ssh tests

* Update cli/configssh.go

Co-authored-by: Cian Johnston <public@cianjohnston.ie>

* Fix requested changes

* Remove socat requirement

* Fix resources not reading in TTY

Co-authored-by: Cian Johnston <public@cianjohnston.ie>

cmd/coder/main.go

@@ -1,14 +1,21 @@
 package main
 
 import (
+	"errors"
+	"fmt"
 	"os"
 
 	"github.com/coder/coder/cli"
+	"github.com/coder/coder/cli/cliui"
 )
 
 func main() {
 	err := cli.Root().Execute()
 	if err != nil {
+		if errors.Is(err, cliui.Canceled) {
+			os.Exit(1)
+		}
+		_, _ = fmt.Fprintln(os.Stderr, cliui.Styles.Error.Render(err.Error()))
 		os.Exit(1)
 	}
 }