[refactor] strict type and user literals for currency amounts

[majestrate]

internally, oxen currency amounts are atomic oxen as a uint64_t, which is not the same as an "oxen". this is an inherited artifact from upstream which has made multiple bugs happen.

we should use an explicitly constructable non ambiguous type for currency amounts with user literals for each denomination. ( 40_$OXEN 40_atomic_$OXEN etc or something )