Support for HTTP method 'POST' for .queryRaw(...) api.

[SamuelToh]

Hi guys,

This is a feature which I thought would be a nice to have. I raised this one because I have somehow hit a HTTP 431 error from influx, Request header too big. My thoughts is that, doing a POST instead of GET should fix my problem

Expected Behavior

Influxdb supports HTTP method GET and POST for its /query endpoint.

Therefore, node-influx should also provide such flexibility. End users should be able to pass in the method key with POST as its value into the .queryRaw(...) method.

Upon doing so, the driver should construct the appropriate payload and send it to influxdb.

Actual Behavior

The method key is ignored.

https://github.com/node-influx/node-influx/blob/master/src/index.ts#L1511-L1517

Only 1 parameter is passed in, which is why method is set to the default GET value.

Steps/Code to Reproduce the Problem

1. 1. 1. Call query() or queryRaw and set method: POST