feature: support lr2

[Catizard]

Support loading lr2 save file. However, lr2 doesn't track record create time, the most feature of lampghost would be unusable. This project's old tui version has already supported importing lr2 save file and implemented some features.

This issue is the tracker of the progress:

• generate equivalent of songdata.db for lr2 users
  • support for subsequent modifications
  • fix missing hash field whenever updating songs
• adding LR2 user as main user
• adding LR2 user as rivals
• generate tags