fix: improve provisioner key cli usability (#14834)

What this changes:
- Unhides the `--key` flag on provisioner start
- Deprecates and hides `provisionerd` command group in favor of
`provisioner(s)`
- Removes org id from `coder provisioner keys list`

docs/reference/cli/provisioner.md

@@ -0,0 +1,22 @@
+<!-- DO NOT EDIT | GENERATED CONTENT -->
+
+# provisioner
+
+Manage provisioner daemons
+
+Aliases:
+
+- provisioners
+
+## Usage
+
+```console
+coder provisioner
+```
+
+## Subcommands
+
+| Name                                         | Purpose                  |
+| -------------------------------------------- | ------------------------ |
+| [<code>start</code>](./provisioner_start.md) | Run a provisioner daemon |
+| [<code>keys</code>](./provisioner_keys.md)   | Manage provisioner keys  |