An IPv6 address from fc00::/8 could be either from the CJDNS network or
from a private-unroutable-reserved segment of IPv6. A seed node with
such an address must be from the CJDNS network, otherwise other peers
will not be able to connect to it.
Flagged by flake8 v3.6.0, as W605, plus a few others identified
incidentally, e.g. 59ffecf66cf4d08c4b431e457b083878d66a3fd6.
Note that r"\n" matches to "\n" under re.match/search.
- Moved all seed related scripts to contrib/seeds for consistency
- Updated `makeseeds.py` to handle IPv6 and onions, fix regular
expression for recent Bitcoin Core versions
- Fixed a bug in `generate-seeds.py` with regard to IPv6 parsing