Support InfluxDB line protocol in scrapers

[maximal]

I like InfluxDB line protocol very much for its simplicity and consistency. So, I usually push data from my services to InfluxDB in this protocol.
Recently, I wanted to switch to the pull-scheme and surprisingly found out that Influx own scrapers do not support Influx’s own protocol :-(

I can write my own scraper, of course, but it would sound logical if InfluxDB supported its own protocol in its scraper.

Proposal:
Let scrapers support not only Prometheus protocol, but InfluxDB line protocol as well.

Current behaviour:
Currently the line protocol isn’t supported.

[maximal]

Meanwhile, I created a command-line scraper to have this functionality.

https://github.com/maximal/influx-scraper