feat: Add agent authentication based on instance ID (#336)

* feat: Add agent authentication based on instance ID

Each cloud has it's own unique instance identity signatures, which
can be used for zero-token authentication. This change adds support
for tracking by "instance_id", and automatically authenticating
with Google Cloud.

* Add test for CLI

* Fix workspace agent request name

* Fix race with adding to wait group

* Fix name of instance identity token

database/query.sql

@@ -328,6 +328,16 @@ WHERE
 LIMIT
   1;
 
+-- name: GetWorkspaceResourceByInstanceID :one
+SELECT
+  *
+FROM
+  workspace_resource
+WHERE
+  instance_id = @instance_id :: text
+ORDER BY
+  created_at;
+
 -- name: GetWorkspaceResourcesByHistoryID :many
 SELECT
   *
@@ -596,12 +606,13 @@ INSERT INTO
     id,
     created_at,
     workspace_history_id,
+    instance_id,
     type,
     name,
     workspace_agent_token
   )
 VALUES
-  ($1, $2, $3, $4, $5, $6) RETURNING *;
+  ($1, $2, $3, $4, $5, $6, $7) RETURNING *;
 
 -- name: UpdateAPIKeyByID :exec
 UPDATE