feat: Add support for item appraisal

[pacampbell]

Added support for special shops which can perform appraisals. An appraisal is a transaction where the player trades either one or more items which are then exchanged for a different item. These items which are given in the exchange come from various content throughout the game. Many of the rewards have crests attached to them which have unique stats which can normally not be obtained through the mounting system.

Checklist:

• [x] The project compiles
• [x] The PR targets develop branch

[pacampbell]

Requires #372 for crest support