* split up mailbox.c
* notify: add global notifications
* neomutt: move AllAccounts
* notify: add Account Events
* refactor users of AllMailboxes
* drop AllMailboxes
* account: add mailbox_add()
* notify: add Mailbox Events
* notify: drop old Context notifications
* config: add config subsets
* config: convert to subset
* mailbox: rename desc to name
* create libcore