Thanks to @yzguy for assisting with API tests to confirm support

The caching of pools for the Constellix provider will now cache based
on the type of pool and the name. Previously it was caching based on
the name only.

In order to add support for pools and other API resources from Constellix, we need to update the base URL to not contain domains and instead specify this where it's needed.

dump does not write invalid value(s) to yaml

`Included` and `Excluded` can be used to filter records for one or more specific provider(s). This can be extremely useful when certain record types are not supported by a provider and you want only that provider to receive an alternative record.

See also: https://github.com/github/octodns/issues/26

Before, 1-2k record took ~10s and more than that was just painful, 5k took
forever. This records things to keep a dict of nodes with a set of records so
that we can quickly "jump" to the point we're looking for without having to
search. 10k records now takes ~5s.

```yaml
ignored:
  octodns:
    ignored: true
  type: A
  value: 1.2.3.4
```