Added user-update API endpoint

- Required changing the docs generator to handle more complex
  object-style rules. Bit of a hack for some types (password).
- Extracted core update logic to repo for sharing with API.
- Moved user update language string to align with activity/logging
  system.
- Added tests to cover.

routes/api.php

@@ -69,4 +69,5 @@ Route::delete('shelves/{id}', [BookshelfApiController::class, 'delete']);
 
 Route::get('users', [UserApiController::class, 'list']);
 Route::get('users/{id}', [UserApiController::class, 'read']);
+Route::put('users/{id}', [UserApiController::class, 'update']);
 Route::delete('users/{id}', [UserApiController::class, 'delete']);