Release 3.0.0 Candidate (#699)

Final changes before V3.0.0 release

* Remove old Gandi.  Fixes #575
* Many cleanups
* go mod tidy && go mod vendor

* integration_test.go: Output subtest name

* Cleanups

* integration_test.go: Description should include sub-test name
* Add a whitespace test to js/parse_tests/017-txt.js

* Cloudflare strips whitespace from end of TXT

* Fixes https://github.com/StackExchange/dnscontrol/issues/700

* Whitespace at end of TXT records

Name.com strips the whitespace from the end of a TXT record. There's
nothing we can do other than file a bug.

* Fixes https://github.com/StackExchange/dnscontrol/issues/701

pkg/js/parse_tests/017-txt.js

@@ -1,6 +1,7 @@
-D("foo.com","none"
-  , TXT("@","simple")
-  , TXT("@",["one"])
-  , TXT("@",["bonie", "clyde"])
-  , TXT("@",["straw", "wood", "brick"])
-);
+D("foo.com","none"
+  , TXT("a","simple")
+  , TXT("b","ws at end ")
+  , TXT("c",["one"])
+  , TXT("d",["bonie", "clyde"])
+  , TXT("e",["straw", "wood", "brick"])
+);

pkg/js/parse_tests/017-txt.json

@@ -9,7 +9,7 @@
       "records": [
         {
           "type": "TXT",
-          "name": "@",
+          "name": "a",
           "target": "simple",
           "txtstrings": [
             "simple"
@@ -17,7 +17,15 @@
         },
         {
           "type": "TXT",
-          "name": "@",
+          "name": "b",
+          "target": "ws at end ",
+          "txtstrings": [
+            "ws at end "
+          ]
+        },
+        {
+          "type": "TXT",
+          "name": "c",
           "target": "one",
           "txtstrings": [
             "one"
@@ -25,7 +33,7 @@
         },
         {
           "type": "TXT",
-          "name": "@",
+          "name": "d",
           "target": "bonie",
           "txtstrings": [
             "bonie",
@@ -34,7 +42,7 @@
         },
         {
           "type": "TXT",
-          "name": "@",
+          "name": "e",
           "target": "straw",
           "txtstrings": [
             "straw",
@@ -45,4 +53,4 @@
       ]
     }
   ]
-}
+}