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.up.sql

@@ -0,0 +1,44 @@
+CREATE TABLE template_version_presets
+(
+	id UUID PRIMARY KEY NOT NULL,
+	template_version_id UUID NOT NULL,
+	name TEXT NOT NULL,
+	created_at TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP,
+	FOREIGN KEY (template_version_id) REFERENCES template_versions (id) ON DELETE CASCADE
+);
+
+CREATE TABLE template_version_preset_parameters
+(
+	id UUID PRIMARY KEY NOT NULL,
+	template_version_preset_id UUID NOT NULL,
+	name TEXT NOT NULL,
+	value TEXT NOT NULL,
+	FOREIGN KEY (template_version_preset_id) REFERENCES template_version_presets (id) ON DELETE CASCADE
+);
+
+ALTER TABLE workspace_builds
+ADD COLUMN template_version_preset_id UUID NULL;
+
+ALTER TABLE workspace_builds
+ADD CONSTRAINT workspace_builds_template_version_preset_id_fkey
+FOREIGN KEY (template_version_preset_id)
+REFERENCES template_version_presets (id)
+ON DELETE SET NULL;
+
+-- Recreate the view to include the new column.
+DROP VIEW workspace_build_with_user;
+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.';