Since the kernel library no longer depends on the system file, move it
to the common library instead in accordance to the diagram in
doc/design/libraries.md.
This is an extraction of ArgsManager related functions from util/system
into their own common file.
Config file related functions are moved to common/config.cpp.
The background of this commit is an ongoing effort to decouple the
libbitcoinkernel library from the ArgsManager. The ArgsManager belongs
into the common library, since the kernel library should not depend on
it. See doc/design/libraries.md for more information on this rationale.
Once we received a reconciliation announcement support
message from a peer and it doesn't violate our protocol,
we store the negotiated parameters which will be used
for future reconciliations.
If we're connecting to the peer which might support
transaction reconciliation, we announce we want to reconcile
with them.
We store the reconciliation salt so that when the peer
responds with their salt, we are able to compute the
full reconciliation salt.
This behavior is enabled with a CLI flag.
