python/resolve_domains: add many features
python/resolve_domains: add many features

* Be case-insensitive when sorting domain names
* Query many PTR records from the command line.
* Allow merging cache files together (this prevents having to handle
  thousands of small JSON files).
* Add many prefixes to the list of well-known ones.
* Document more often-used cloud providers.
* Resolve SRV records too.
* Warn about DNSPython's ANY lack of support once.
* Detect and merge wildcard records.

fishilico/shared,fishilico/shared,fishilico/shared,fishilico/shared,fishilico/shared,fishilico/shared,fishilico/shared