feat: Add new German localization strings

[lndr0x]

This pull request expands the German localization (de.yaml) for the XMCL Keystone UI by adding numerous new translations and enhancing existing sections. The changes cover new UI features, improved descriptions, and additional options across mods, instances, saves, resource packs, shaders, multiplayer, and sorting. These updates aim to improve the user experience for German-speaking users by providing more comprehensive and accurate translations.

Key localization additions and improvements:

Mod and Resource Pack Enhancements:

• Added translations for mod-related terms such as description, license, versions, and new messages for mod installation, including loading versions, no versions available, and reinstall options. Also added resource pack search and empty state messages. [1] [2] [3] [4] [5]
• Added new fields for shader packs, including market, search, and empty state messages.

Instance and Save Management:

• Introduced translations for duplicating instances, deleting instance files, searching and displaying all instances, and importing PrismLauncher instances. [1] [2] [3]
• Added new fields for save management, such as difficulty, mouse controls, and screenshot gallery features. [1] [2]

Game and Multiplayer Features:

• Added translations for difficulty levels, installing profiles and Quilt, modpack export, Minecraft migration, and multiplayer connection errors with hints. [1] [2] [3] [4] [5]

User Interface and Sorting:

• Enhanced sorting options in the sidebar with a new "Sort by name" translation.
• Added various UI labels for download mod metadata database, reinstalling versions, and allowing cheats. [1] [2] [3]

These updates collectively provide a more complete and user-friendly German interface for the application.