feat: add shared_with_group: and shared_with_user: filters to /workspaces endpoint (#19875)

Adds shared_with_user and shared_with_group filters to the /workspaces
endpoint.

- `shared_with_user`: filters workspaces shared with a specific user.
Accepts a user UUID or username.
- `shared_with_group`: filters workspaces shared with a specific group.
Accepts:
  - a group UUID, or
  - `<organization name>/<group name>`, or
  - `<group name>` (resolved in the default organization).


Closes
[coder/internal#1004](https://github.com/coder/internal/issues/1004)

coderd/database/queries/workspaces.sql

@@ -384,7 +384,18 @@ WHERE
 			(workspaces.user_acl != '{}'::jsonb OR workspaces.group_acl != '{}'::jsonb) = sqlc.narg('shared') :: boolean
 		ELSE true
 	END
-
+	-- Filter by shared_with_user_id
+	AND CASE
+		WHEN @shared_with_user_id :: uuid != '00000000-0000-0000-0000-000000000000'::uuid THEN
+			workspaces.user_acl ? (@shared_with_user_id :: uuid) :: text
+		ELSE true
+	END
+	-- Filter by shared_with_group_id
+	AND CASE
+		WHEN @shared_with_group_id :: uuid != '00000000-0000-0000-0000-000000000000'::uuid THEN
+			workspaces.group_acl ? (@shared_with_group_id :: uuid) :: text
+		ELSE true
+	END
 	-- Authorize Filter clause will be injected below in GetAuthorizedWorkspaces
 	-- @authorize_filter
 ), filtered_workspaces_order AS (