This commit refactors the Store interface in State into smaller
interfaces in package store. These interfaces are combined into one
structure called a "Cabinet". The default implementation of those
interfaces have been rewritten in package defaultstore, while the old
no-op implementation stays with the store package.
This commit also omitted several state handlers for user events, as it
is unclear what they are actually structured like.
This addresses discord/discord-api-docs#1440.
State documentation has been added, which documents the store and
handlers as well.
Bug fixes include:
- PreHandler being called after the state handler; it is now called
before as documented.
- Minor behavior changes regarding Guild Create events. Refer to State's
documentation.
diamondburned
