Add plugin for Azure DNS (#2945)

* Add plugin for Azure DNS

Signed-off-by: darshanime <deathbullet@gmail.com>

* Rename AzureDNS plugin to Azure

Signed-off-by: darshanime <deathbullet@gmail.com>

* remove upstream from azure syntax

Signed-off-by: darshanime <deathbullet@gmail.com>

* Rename azure plugin block keynames

Signed-off-by: darshanime <deathbullet@gmail.com>

* Normalize zone name before lookup in zones

Signed-off-by: darshanime <deathbullet@gmail.com>

* Update import path for caddy

Signed-off-by: darshanime <deathbullet@gmail.com>

* normalize azure zone name only if required

Signed-off-by: darshanime <deathbullet@gmail.com>

* Add support for MX, SRV, TXT, records

Signed-off-by: darshanime <deathbullet@gmail.com>

* Add specs for new record types

Signed-off-by: darshanime <deathbullet@gmail.com>

* Use sequential updates for zones

Signed-off-by: darshanime <deathbullet@gmail.com>

* Add OWNERS file for azure plugin

Signed-off-by: darshanime <deathbullet@gmail.com>

* Rename imports for third party packages

Signed-off-by: darshanime <deathbullet@gmail.com>

* Capitalize values in README

Signed-off-by: darshanime <deathbullet@gmail.com>

* Shorten keys for azure plugin config

Signed-off-by: darshanime <deathbullet@gmail.com>

* Fixup readme for azure plugin

Signed-off-by: darshanime <deathbullet@gmail.com>

plugin/azure/setup_test.go

@@ -0,0 +1,72 @@
+package azure
+
+import (
+	"testing"
+
+	"github.com/caddyserver/caddy"
+)
+
+func TestSetup(t *testing.T) {
+	tests := []struct {
+		body          string
+		expectedError bool
+	}{
+		{`azure`, false},
+		{`azure :`, true},
+		{`azure resource_set:zone`, false},
+		{`azure resource_set:zone {
+    tenant
+}`, true},
+		{`azure resource_set:zone {
+    tenant
+}`, true},
+		{`azure resource_set:zone {
+    client
+}`, true},
+		{`azure resource_set:zone {
+    secret
+}`, true},
+		{`azure resource_set:zone {
+    subscription
+}`, true},
+		{`azure resource_set:zone {
+    upstream 10.0.0.1
+}`, true},
+
+		{`azure resource_set:zone {
+    upstream
+}`, true},
+		{`azure resource_set:zone {
+    foobar
+}`, true},
+		{`azure resource_set:zone {
+    tenant tenant_id
+    client client_id
+    secret client_secret
+    subscription subscription_id
+}`, false},
+
+		{`azure resource_set:zone {
+    fallthrough
+}`, false},
+		{`azure resource_set:zone {
+		environment AZUREPUBLICCLOUD
+	}`, false},
+		{`azure resource_set:zone resource_set:zone {
+			fallthrough
+		}`, true},
+		{`azure resource_set:zone,zone2 {
+			fallthrough
+		}`, false},
+		{`azure resource-set {
+			fallthrough
+		}`, true},
+	}
+
+	for i, test := range tests {
+		c := caddy.NewTestController("dns", test.body)
+		if _, _, _, err := parse(c); (err == nil) == test.expectedError {
+			t.Fatalf("Unexpected errors: %v in test: %d\n\t%s", err, i, test.body)
+		}
+	}
+}