WIP: Support chart command in PPL

[yuancu]

Description

The chart command returns an aggregation result in a two-dimension table format.

TODOs:

• support span
• support limit, limit=top x, limit=bottom x
• support useother, otherstr
• correct limit behavior with all aggregation functions (min, max, avg, etc) // fixed in Fix timechart OTHER category aggregation for non-cumulative functions #4594
• support usenull, nullstr

Related Issues

Resolves #399

Check List

• New functionality includes testing.
• New functionality has been documented.
• New functionality has javadoc added.
• New functionality has a user manual doc added.
• New PPL command checklist all confirmed.
• API changes companion pull request created.
• Commits are signed per the DCO using --signoff or -s.
• Public documentation issue/PR created.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.