This is an encapsulation of the common work done by all of our
single-client IPC servers on startup:
1. Create a Core::LocalSocket, taking over an accepted fd.
2. Create an application-specific ClientConnection object,
wrapping the socket.
It's not a huge change in terms of lines saved, but I do feel that it
improves expressiveness. :^)
Unused sockets created by EnsureConnection should not keep the socket
around (storing a strong reference will create a reference cycle).
This fixes a whole bunch more RS spins.
We need to set the root certificates, and tell the connection cache that
the preconnect job finished (otherwise it would spin forever, waiting
for us to tell it that).
The current ProtocolServer was really only used for requests, and with
the recent introduction of the WebSocket service, long-lasting
connections with another server are not part of it. To better reflect
this, this commit renames it to RequestServer.
This commit also changes the existing 'protocol' portal to 'request',
the existing 'protocol' user and group to 'request', and most mentions
of the 'download' aspect of the request to 'request' when relevant, to
make everything consistent across the system.
Note that LibProtocol still exists as-is, but the more generic Client
class and the more specific Download class have both been renamed to a
more accurate RequestClient and Request to match the new names.
This commit only change names, not behaviors.
