InfluxDb Parser and Source

[vjkoskela]

Add a new parser implementation for the InfluxDb line format. Then add a new source implementation that provides reasonable defaults for a InfluxDb source (e.g. default port is 8086 for http and 8089 for udp).

Reference:

• https://docs.influxdata.com/influxdb/v1.6/write_protocols/line_protocol_tutorial/
• https://docs.influxdata.com/influxdb/v1.6/tools/api/#write