Add non-blocking InfluxDB sink (#29)

* Add non-blocking InfluxDB sink

* Add configurable batch size

sinks/influxAsyncSink.md

@@ -0,0 +1,34 @@
+## `influxasync` sink
+
+The `influxasync` sink uses the official [InfluxDB golang client](https://pkg.go.dev/github.com/influxdata/influxdb-client-go/v2) to write the metrics to an InfluxDB database in a **non-blocking** fashion. It provides only support for V2 write endpoints (InfluxDB 1.8.0 or later).
+
+
+### Configuration structure
+
+```json
+{
+  "<name>": {
+    "type": "influxasync",
+    "meta_as_tags" : true,
+    "database" : "mymetrics",
+    "host": "dbhost.example.com",
+    "port": "4222",
+    "user": "exampleuser",
+    "password" : "examplepw",
+    "organization": "myorg",
+    "ssl": true,
+    "batch_size": 200,
+  }
+}
+```
+
+- `type`: makes the sink an `influxdb` sink
+- `meta_as_tags`: print all meta information as tags in the output (optional)
+- `database`: All metrics are written to this bucket 
+- `host`: Hostname of the InfluxDB database server
+- `port`: Portnumber (as string) of the InfluxDB database server
+- `user`: Username for basic authentification
+- `password`: Password for basic authentification
+- `organization`: Organization in the InfluxDB
+- `ssl`: Use SSL connection
+- `batch_size`: batch up metrics internally, default 100