They currently fit the general concept of a `request::` in the sense
that they are not property related and have "request handlers".
The commit also add deprecation for signals.
The reason for this fits within the larger standardization project.
Non-namespaced signals will eventually be renamed. This has started
a long time ago.
What is old is new again. Once upon a time, there was a `startup`
parameter to the `manage` signal. It is now back in the form of
a context.
Finally, this commit removes the `manage` section of `rc.lua`. It no
longer did anything worthy of being in the config. Each of its
important parts have been moved out over the years and the last
remaining bit is always required anyway. The code has been moved
to `client.lua`.