Documentation for the funderupdate command on the funder plugin.
Realized we were missing the "leases_only" in the output; also adds
'_msat' to msat denominated outputs so they're parsed correctly by our
python bindings (also matches our naming conventions)
Changelog-EXPERIMENTAL: funder: `funderupdate` command to view and update params for contributing our wallet funds to v2 channel openings. Provides params for enabling `option_will_fund`.