Since the code for creating and using a macaroon service is the same for
multiple projects (pool, loop, litd etc), the code has been unified in
lndclient. So this commit removes the macaroon service code and instead
uses the lndclient code.
This commit bumps the _compile time_ version of lnd to v0.13.0-beta.rc2.
This does not have an effect on the user, the run time backward compatibility
will be preserved. Only the next commit will bump that minimum version.
To make sure we don't just block for forever if another Loop daemon
process is already running, we add a timeout and error out if obtaining
the unique file lock fails after 5 seconds.
To itest our autolooper, we need to be able to trigger dispatch on
demand. This functionality is included in a separate rpc server behind
a dev flag. Since it is unlikely that we need to split loop into
multiple rpc servers, this commit simply adds an additional debug server
rather than opting for a full subserver setup.
When loopd runs in the same process as lnd (in LiT), it hooks itself
into lnd's RPC server as an external subserver. But because the user
should still be able to use the default loop macaroon, the loop daemon
must be able to validate its own macaroons as lnd's macaroon service
doesn't know the root key for it.
This allows Loop users to further improve their privacy by not revealing
their source IP address. Note that the identity of the lnd node behind
Loop can still be revealed when performing a Loop In due to the swap
server extending an off-chain HTLC to the user.
Onion addresses don't yet exist for the swap servers, but they will be
added at a later time.
