[44net] DNS cleanup

With the kind cooperation of Neil Johnson, I've identified nearly 15000 entries in the AMPR.ORG DNS that I feel can go away. What was done was to create a list of valid subnets of network 44 by combining the encap list, the list of BGP-advertised subnets, and extracting all the connected or end-user subnets listed in the portal. We then made a list of all the DNS entries that no longer fall into any of those subnets. This is nearly half the "A" records in the DNS. That list is available for review by anonymous FTP from hamradio.ucsd.edu. The file is called "to-be-deleted.txt". I encourage everyone who has a DNS entry to fetch a copy of the file and make sure that we haven't accidently included any entries that need to remain in the DNS. Please let me know of any such entries and I can remove them from the list. Assuming our scheme worked, around the beginning of next month, March, I will process the list and remove those entries from the DNS. We still have a long ways to go but this will help. Thank you. - Brian