* Merge traits ToApub and FromApub into ApubObject
* Rewrite community outbox to use new fetcher
* Rewrite community moderators collection
* Rewrite tombstone
* start to implement apub inbox routing lib
* got something that almost works
* it compiles!
* implemented some more
* move library code to separate crate (most of it)
* convert private message handlers
* convert all comment receivers (except undo comment)
* convert post receiver
* add verify trait
* convert community receivers
* add cc field for all activities which i forgot before
* convert inbox functions, add missing checks
* convert undo like/dislike receivers
* convert undo_delete and undo_remove receivers
* move block/unblock activities
* convert remaining activity receivers
* reimplement http signature verification and other checks
* also use actor type for routing, VerifyActivity and SendActivity traits
* cleanup and restructure apub_receive code
* wip: try to fix activity routing
* implement a (very bad) derive macro for activityhandler
* working activity routing!
* rework pm verify(), fix tests and confirm manually
also remove inbox username check which was broken
* rework following verify(), fix tests and test manually
* fix post/comment create/update, rework voting
* Rewrite remove/delete post/comment, fix tests, test manually
* Rework and fix (un)block user, announce, update post
* some code cleanup
* rework delete/remove activity receivers (still quite messy)
* rewrite, test and fix add/remove mod, update community handlers
* add docs for ActivityHandler derive macro
* dont try to compile macro comments
