Add RWTH provider (#1629)

* Add RWTH provider

* fix Owners order

* Reorganize RWTH Provider

* Fix staticcheck and code style issues

Co-authored-by: Tom Limoncelli <tlimoncelli@stackoverflow.com>

docs/_providers/rwth.md

@@ -0,0 +1,43 @@
+---
+name: RWTH
+title: RWTH DNS-Admin Provider
+layout: default
+jsId: RWTH
+---
+# RWTH DNS-Admin Provider
+
+## Configuration
+
+To use this provider, add an entry to `creds.json` with `TYPE` set to `RWTH`
+along with your [API Token](https://noc-portal.rz.rwth-aachen.de/dns-admin/en/api_tokens).
+
+Example:
+
+```json
+{
+  "rwth": {
+    "TYPE": "RWTH",
+    "api_key": "bQGz0DOi0AkTzG...="
+  }
+}
+```
+
+## Metadata
+This provider does not recognize any special metadata fields unique to it.
+
+## Usage
+An example `dnsconfig.js` configuration:
+
+```js
+var REG_NONE = NewRegistrar("none");
+var DSP_RWTH = NewDnsProvider("rwth");
+
+D("example.rwth-aachen.de", REG_NONE, DnsProvider(DSP_RWTH),
+    A("test", "1.2.3.4")
+);
+```
+
+## Caveats
+The default TTL is not automatically fetched, as the API does not provide such an endpoint.
+
+The RWTH deploys zones every 15 minutes, so it might take some time for changes to take effect.