Custom gameplay backup intervals per game

[sharkusmanch]

It might be useful for some games to have a custom gameplay save backup interval that is different than the global.

Ex: "Souls" games or other games with aggressive auto save and only a single game save file

• Create extension tags for predetermined backup intervals (1,5,10,15,60) minutes
• Add right click context menu options for adding these tags to selected game
• Update backup logic to support