Backend for roa-sets. This combines as_sets and prefix-set tries to do

Backend for roa-sets. This combines as_sets and prefix-set tries to do
proper ROA checking. There is a new match function trie_roa_check which
does a trie traversal and looks for candidates and matches. If prefix
is not covered then ROA_UNKNOWN is returned, if prefix is covered by an
entry it will return ROA_INVALID unless the source-as / maxlen combo is
matching (ROA_VALID).
OK and input sthen@