Fix libdns::Record to dnsmadeeasy::Record translation

[coandco]

I'm not sure when DNSMadeEasy tweaked their API, but there are now several incompatibilities with the module as it exists. Specifically:

1. The CreateRecords call now returns the value of the created record wrapped in spurious/non-existent quotes (see CreateRecords problem #3). This removes them.
2. DNSMadeEasy no longer accepts a TTL of 0 (which certmagic passes us by default unless it's set specifically), so dmeRecordFromRecord will now set a default value of 120 if the value is 0.
3. Similarly, they require a value to be set for GtdLocation from the possible values DEFAULT, US_EAST, US_WEST, EUROPE, ASIA_PAC, OCREANIA, SOUTH_AMERICA. We set it to DEFAULT.
4. Finally, if we get passed a blank string for record.ID, we translate it to 0 in the dmeRecord struct, so it will properly be omitted thanks to the json:"id,omitempty" tag on the dmeRecord.ID item.

[coandco]

I've verified that this works alongside my parallel pull request John-K/dnsmadeeasy#4 by running the following xcaddy command:

xcaddy build --with github.com/caddy-dns/dnsmadeeasy --with github.com/libdns/dnsmadeeasy=github.com/coandco/[email protected] --with github.com/john-k/dnsmadeeasy=github.com/coandco/[email protected]

The resulting binary successfully obtains certs using the DNS01 challenge on DNSMadeEasy.