deterministic output for rba dict

[pyth0n1c]

define serialization functions
for rba and risk bits in line with
normal pydantic workflow.

There is currently an issue where, because RBA objects now exist in a set,
the serialization order when writing to conf files can change. Because
of that, the contentctl inspect metadata validation flow can detect
non-meaningful changes in a conf file which, nevertheless, require
bumping version of a detection due to conf file changes.

[ljstella]

LGTM