#1457 RFC: Include the provider type in creds.json, remove it from dnsconfig.js

[Tom Limoncelli]

Hey DNSControl folks!

Problem: Many commands and functions require the user to specify the provider name (such as ROUTE53) and the cred-name. This is redundant, error prone, and additional cognitive load on the user.

Proposed solution: Store the provider name in the individual creds.json entries themselves; thus removing the need to specify them in dnsconfig.js or on the command line.

There are 3 proposed syntaxes.  FEEDBACK REQUESTED!

        https://github.com/StackExchange/dnscontrol/issues/1457

OLD:

dnsconfig.js:

          var REG_GANDI = NewRegistrar("gandi", "GANDI_V5");
          var DSP_CF = NewDnsProvider("cloudflare_tal", "CLOUDFLAREAPI");
Bash:

          $ dnscontrol get-zones cloudflare_tal CLOUDFLAREAPI

NEW:

dnsconfig.js:

          var REG_GANDI = NewRegistrar("gandi");
          var DSP_CF = NewDnsProvider("cloudflare_tal");
Bash:

          $ dnscontrol get-zones cloudflare_tal

Best,

Tom Limoncelli