Add common expedition base class
Use repository for zone and world expedition caching
World now stores members and leader as Member objects instead of ids
This improves readability of the caching methods and lets world cache
expedition dzs and members like zone. World also now caches expeditions
as unique_ptr which will be necessary for future dz callback lambdas
that capture 'this' so addresses don't change on cache vector resizes.
* Insert repository improvements
* Remove no longer necessary code, remove license banner since we have a license at the repo level
* Update template comments
