fix(core/query): remove influxql support #195

[sranka]

Fixes #195

This PR removes support for influxql queries in the query API, there are multiple reasons for doing this:

• the state of support of influxql queries in InfluxDB 2.0 is unknown and not documented
• the server returns json data to influxql query, such data is not parseable by this client that expect CSV data as the only option explained by the docs
• even 1.x server does not support influxql in 2.0 compatibility API

Checklist

• CHANGELOG.md updated
• A test has been added if appropriate
• yarn test completes successfully
• Commit messages are in semantic format
• Sign CLA (if not already signed)

[sezanzeb]

This might be outdated, and I would like influxql support to be added back in, because it responds data in "wide" format, as opposed to the "narrow" format of flux

the state of support of influxql queries in InfluxDB 2.0 is unknown and not documented

InfluxQL is supported in 2.x (see below) and even 3.x: https://www.influxdata.com/blog/introducing-influxdb-3-0/

the server returns json data to influxql query, such data is not parseable by this client that expect CSV data as the only option explained by the docs

By setting the Accept header data is returned in csv

Example:

curl --request POST \
        "http://localhost:8086/query"  \
        --header 'Authorization: Token testtoken' \
        --header 'Accept: application/csv' \
        --data "q=SELECT * FROM testproject..bar WHERE device = 'foo'"