GWResolver: Increase logging verbosity

This patch adds a bunch of extra logging to the gateway resolver thread.
For the moment, these are set to INFO level. If it becomes to spammy in
future, we should probably decrease to DEBUG.

Signed-off-by: Joe Stringer <joe@wand.net.nz>
rfserver: Send IPv6-based BGP to controller

Signed-off-by: Joe Stringer <joe@wand.net.nz>