add Apache Comet

[Iskander14yo]

This PR adds Apache Comet as a backend for Spark in analytical workloads. Base issue - #517.

Notes:

• I did not rewrite the queries as initially proposed in the issue. This can be done later — for now, I’d like to focus on verifying setup correctness.
• I tried to reuse existing Spark code in the form of copy-paste-document.

Also I consider creating issue in Comet repo for devs to double-check my configuration. This is especially important since there are 1 query that failed and other questionable moments. Meanwhile, I'd glad to hear comments from interested.

[CLAassistant]

All committers have signed the CLA.

[rschu1ze]

These machine types were measured for Spark: c6a.2xlarge.json c6a.4xlarge.json c6a.xlarge.json c8g.4xlarge.json

Do you plan to add them as well or do you like me to do this?

[Iskander14yo]

I can probably run that too after we finalize discussion on the PR.

[Iskander14yo]

@rschu1ze Currently I'm solving AWS issues related to my account and I don't know how long this will take. If you have an opportunity to run bench yourself I'd appreciate it. Otherwise I'll run it myself as soon as possible.

[rschu1ze]

The PR LGTM. It will be hard for me to capture measurements on c6a.2xlarge.json, c6a.4xlarge.json, c6a.xlarge.json, and c8g.4xlarge.json in the next 1.5 weeks but if you find some time, please go ahead. Otherwise or if this is urgent, I can also merge this PR (just lmk).

[alexey-milovidov]

@rschu1ze, we have the automation - please go ahead and merge. Then we can run on any machines in a matter of a single command.

[Iskander14yo]

@alexey-milovidov current VM's (c6a.4xlarge) results should be re-run too since last changes.