pour the foundations for rpc, and let them set. this is very much
unstable and must be opted into with explicit store uris (e.g. by
setting `NIX_REMOTE=daemon?protocol=any`). the daemon sockets are
not enabled by default and must be enabled with the `rpc-sockets`
experimental feature. we will not advertise this just yet because
in the current state it one has to be *very* dedicated to the rpc
cause to deploy this, but once we have some more bits migrated we
may want to add release notes and officially as for beta testing.
Co-Authored-By: piegames <git@piegames.de>
Change-Id: I85a96ccb700b91190c1eb37154bcc6ae1c03401a
