Hardcoded constants set to 16777215

[tsjk]

During the infancy of the lightning network, channel sizes could be at most 16777215 satoshi. This is no longer so, and larger channel sizes are allowed by default in recent versions of Core Lightning. We should therefore change constants that build on that this is the maximal channel size:
https://github.com/ZmnSCPxj/clboss/blob/b6795c43dc646225902845c81c4a4df3fea532e7/Boss/Mod/AmountSettingsHandler.cpp#L19
https://github.com/ZmnSCPxj/clboss/blob/b6795c43dc646225902845c81c4a4df3fea532e7/Boss/Mod/ChannelCreationDecider.cpp#L39

These settings could either be set to some big value, like 1 BTC, or be user settable.

While we are at it, we might as well increase
https://github.com/ZmnSCPxj/clboss/blob/b6795c43dc646225902845c81c4a4df3fea532e7/Boss/Mod/AmountSettingsHandler.cpp#L23
to 100k satoshi, to accommodate for most new channels created now being anchored - and thus a larger reserve is needed in the case for bumping force closures.