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>

develop.sh

@@ -14,5 +14,5 @@ cd "${PROJECT_ROOT}"
 (
   trap 'kill 0' SIGINT
   CODERV2_HOST=http://127.0.0.1:3000 INSPECT_XSTATE=true yarn --cwd=./site dev &
-  go run cmd/coder/main.go start --dev --tunnel=false
+  go run cmd/coder/main.go start --dev --skip-tunnel
 )