Add system to add new mods from UI

[GoosiferIO]

• Add an 'add mod' button to UI
• Implement modal with fields that populate mod meta data from user I/O and parsed meta.toml file
• Add feature that scans installed lang files if meta.toml file is missing to fill missing mod title for objects
• Should be able to drag and drop a ztd onto modlist
• (Maybe) also support drag and drop .zip files and scan for ztd files