Store Search

Adds a search function to the in-game store. Pressing the F key (configurable) when the store menu is open will display a search dialog.

The search function supports the following fields
- Equipment name (e.g. 'Vario')
- Brand name (e.g. 'Massey')
- Mod name (e.g. 'Allis')
- Mod author (e.g. 'Giants')