feat: add CODER_WORKSPACE_HOSTNAME_SUFFIX (#17268)

Adds deployment option `CODER_WORKSPACE_HOSTNAME_SUFFIX`. This will eventually replace `CODER_SSH_HOSTNAME_PREFIX`, but we will do this slowly and support both for `coder ssh` for some time.

Note that the name is changed to "workspace" hostname, since this suffix will also be used for Coder Connect on Coder Desktop, which is not limited to SSH.

coderd/apidoc/docs.go

@@ -12019,6 +12019,9 @@ const docTemplate = `{
                 "wildcard_access_url": {
                     "type": "string"
                 },
+                "workspace_hostname_suffix": {
+                    "type": "string"
+                },
                 "write_config": {
                     "type": "boolean"
                 }