Laravel code quality improvements.

[simjanos-dev]

This is a long list of tasks to improve the code quality. I will probably implement them throughout multiple updates.

Tasks:

• [ ] Replace the TextBlock model with a TextBlock service
• [ ] Move Goal related logic to a new GoalService class (look inside word and phrase model setStage functions)
• [ ] Laravel 11 and PHP 8.3 Update
• [ ] Rename "base_word" to "lemma" #99
• [ ] Rename lessons to chapters #20
• [ ] Rename stage to level
• [ ] Try and catch blocks should be moved from app/Services/AnkiApiService.php to app/Http/Controllers/AnkiController.php.
• [ ] After LinguaCafe has been updated to Laravel 11, GetSubtitleFileContentRequest validation should also check the subtitle file's extension.

Rename media player:

• [ ] Rename MediaPLayerController to JellyfinController
• [ ] Rename MediaPlayerCache model and database to JellyfinSubtitleCache

Moving business logic from controllers to service classes and DB logic into models, replacing return values with proper HTTP responses, and creating request classes and writing proper validations:

• [x] AnkiController
• [x] BookController
• [x] ChapterController
• [ ] DictionaryController
• [ ] GoalController
• [x] HomeController
• [x] ImageController
• [x] ImportController
• [ ] MediaPlayerController
• [x] ReviewController
• [x] SettingsController
• [x] UserController
• [x] VocabularyController