feat(coderd/database): add support for presets (#16509)

This pull requests adds the necessary migrations and queries to support
presets within the coderd database. Future PRs will build functionality
to the provisioners and the frontend.

coderd/database/migrations/000291_workspace_parameter_presets.down.sql

@@ -0,0 +1,29 @@
+-- DROP the workspace_build_with_user view so that we can recreate without
+-- workspace_builds.template_version_preset_id below. We need to drop the view
+-- before dropping workspace_builds.template_version_preset_id because the view
+-- references it. We can only recreate the view after dropping the column,
+-- because the view needs to be created without the column.
+DROP VIEW workspace_build_with_user;
+
+ALTER TABLE workspace_builds
+DROP COLUMN template_version_preset_id;
+
+DROP TABLE template_version_preset_parameters;
+
+DROP TABLE template_version_presets;
+
+CREATE VIEW
+    workspace_build_with_user
+AS
+SELECT
+    workspace_builds.*,
+    coalesce(visible_users.avatar_url, '') AS initiator_by_avatar_url,
+    coalesce(visible_users.username, '') AS initiator_by_username
+FROM
+    workspace_builds
+    LEFT JOIN
+        visible_users
+    ON
+        workspace_builds.initiator_id = visible_users.id;
+
+COMMENT ON VIEW workspace_build_with_user IS 'Joins in the username + avatar url of the initiated by user.';