Remove SendActivity and Perform traits, rely on channel (#3596)

Remove SendActivity and Perform traits, rely on channel (#3596)

* Remove SendActivity and Perform traits, rely on channel

These traits arent necessary anymore now that websocket is removed.
Removing them allows us to use normal actix http handler methods
which are much more flexible, and allow using different middlewares
as well as setting response attributes.

* compiling and create post federating

* clippy

* rename methods, join outgoing activities task

* fix api tests

* no unwrap

* conditional compile

* add back getrandom

* make crates optional

* fmt