Improve activity parsing (split activities, user specified activity lists)

[norbert-k]

Split activity parsing in sub-activities and let users to specify their own activity list

1. Split activities into sub-modules (minigame/default activities, boss activities, raid activities etc..).
2. Allow to specify custom activity lists

When moving to sub-module activity implementation, library will be able to handle changing API responses to a certain degree (default activities will get parsed), while activities at the bottom of list might get corrupted and/or mis-matched. To escape this, users should be able to specify their own activities, so dependency on this library to parse activity data correctly could be improved by allowing developers to handle API changes themselves, instead of relying on ex_osrs_api updates (patches).