Adding Favourites as another tab

I added another tab to Loot Navigation panel called Favourites,
as well as corresponding boost. Player can enter names or aliases
of up to 20 boosts, and remove them on the one by one basis. List
is stored in savefile, and also gets exported//imported.

Further testing may be needed, as well as considerations for price
or unlocking requirements, and general boost format.
Removing persisted storage
Moving storage to saveData(saving ids), and other tweaks

Boosts is now unlocked when player has more than 100 boosts,
and costs 10K sand, 10K castles.
Changing price of the boost to 20G
Merge pull request #1228 from erp-lsf/#1219

Adding Favourites as another tab