NEW PROVIDER: GANDI_V5 (deprecates GANDI) (#572)

* GANDI_v5: Add Registrar support
* Add GANDI deprecation warning
* vendor github.com/tiramiseb/go-gandi

docs/_providers/gandi_v5.md

@@ -0,0 +1,62 @@
+---
+name: Gandi_v5
+title: Gandi_v5 Provider
+layout: default
+jsId: GANDI
+---
+# Gandi_v5 Provider
+
+`GANDI_V5` uses the v5 API and can act as a registrar provider
+    or a DNS provider. It is only able to work with domains
+    migrated to the new LiveDNS API, which should be all domains.
+    API keys are assigned to particular users.  Go to User Settings,
+    "Manage the user account and security settings", the "Security"
+    tab, then regenerate the "Production API key".
+
+* API Documentation: https://api.gandi.net/docs
+* API Endpoint: https://api.gandi.net/
+
+## Configuration
+In your credentials file you must provide your Gandi.net API key.
+The [sharing_id](https://api.gandi.net/docs/reference/) is optional.
+
+{% highlight json %}
+{
+  "gandi_v5": {
+    "apikey": "your-gandi-key",
+    "sharing_id": "your-sharing_id"
+  }
+}
+{% endhighlight %}
+
+## Metadata
+This provider does not recognize any special metadata fields unique to Gandi.
+
+## Usage
+Example Javascript:
+
+{% highlight js %}
+var GANDI = NewDnsProvider("gandi", "GANDI_V5");
+var REG_GANDI = NewRegistrar("gandi", "GANDI_V5");
+
+D("example.tld", REG_GANDI, DnsProvider(GANDI),
+    A("test","1.2.3.4")
+);
+{% endhighlight %}
+
+If you are converting from the old "GANDI" provider, simply
+change "gandi" to "gandi_v5" in `creds.json`, and change "GANDI"
+to "GANDI_V5" in `dnsconfig.js`.  Be sure to test with
+`dnscontrol preview` before running `dnscontrol push`
+
+## New domains
+If a domain does not exist in your Gandi account, DNSControl will *not* automatically add it with the `create-domains` command. You'll need to do that via the web UI manually.
+
+
+## Common errors
+
+This is the error you'll see if your API key is invalid.
+
+```
+Error getting corrections: 401: The server could not verify that you authorized to access the document you requested. Either you supplied the wrong credentials (e.g., bad api key), or your access token has expired
+```