Add additional APIs for requesting more specific details of zones and records

[aeden]

Note that these API changes are intended to be completely backwards compatible with the current caller expecations. In the future the zones API will likely change to make meta-only the only behavior, removing the parameter.

Depends on dnsimple/erldns#118

Example of getting only zone metadata:

curl -i -u "username:password" "http://localhost:8083/zones/example.com?metaonly=1" -H "Accept:application/json"
HTTP/1.1 200 OK
content-length: 138
content-type: application/json
date: Fri, 23 Oct 2020 14:02:02 GMT
server: Cowboy
vary: accept

{"erldns":{"zone":{"name":"example.com","version":"03f9b1ecc0b8ba95286b0425f39bf5e9607ed9d9eaad121be04f0853c1e79758","records_count":15}}}

Example of getting details for records with a specific record name:

curl -i -u "username:password" "http://localhost:8083/zones/example.com/records/www.example.com" -H "Accept:application/json"
HTTP/1.1 200 OK
content-length: 534
content-type: application/json
date: Sat, 24 Oct 2020 08:58:00 GMT
server: Cowboy
vary: accept

[{"name":"www.example.com.","type":"A","ttl":3600,"content":"4.5.6.7"},{"name":"www.example.com.","type":"RRSIG","ttl":3600,"content":"1 8 3 3600 1610635684 1602859684 41299 <<101,120,97,109,112,108,101,46,99,111,109>> \\�Z�o�����ٸ�\u001f\u001d�U\u0011v�fbм\u0017��Ͻ?\u001a0�ͬ�v\u0000\u001b�ާ�\u001bJ\bP���E��=C4��\u0015\u000b!�5[�(a���ԫ\u0013\u0005\u0014pP蕵F�ƒ��q���\u0017%��m�j:�̿{�-ARBY��\u0006Z\u0014\u001b�\f\u000fg�8hs\u00041E�"}]

Example of getting details for records with a specific record name and type:

curl -i -u "username:password" "http://localhost:8083/zones/example.com/records/example.com?type=NS" -H "Accept:application/json"
HTTP/1.1 200 OK
content-length: 309
content-type: application/json
date: Sat, 24 Oct 2020 09:02:36 GMT
server: Cowboy
vary: accept

[{"name":"example.com.","type":"NS","ttl":3600,"content":"ns1.dnsimple.com."},{"name":"example.com.","type":"NS","ttl":3600,"content":"ns2.dnsimple.com."},{"name":"example.com.","type":"NS","ttl":3600,"content":"ns3.dnsimple.com."},{"name":"example.com.","type":"NS","ttl":3600,"content":"ns4.dnsimple.com."}]

[aeden]

@weppos I added you for review of the API design.

@m0rcq I added you for review of the erlang implementation.