WIP, ENH: rich-click CLI

[tylerjereddy]

• related to ENH: pydarshan via rich-click CLI? #808

• adopt rich-click for the pydarshan summary report CLI, with basic usage and heatmap option blocks; example help display:

• switch to darshan_summary as a console script that doesn't require prefixing with python -m ..; so new incantation looks like darshan_summary --log_path treddy_runtime_heatmap_inactive_ranks.darshan and reports the processing time in seconds automatically

• there were two motivations for the above change: 1) simplify the command the user needs to remember 2) I almost always want to know how long the processing took, so report that time by default

• this is just a skeleton, and doesn't actually hook in the HEATMAP options to actual changes in the report (yet); one other caveat is that the console script is less friendly for developers that use an "editable install" so you need to use pip install . instead of pip install -e ., which is a bit annoying, but probably lower priority than user experience concerns/improvements

• some TODOs may include:

• remove the old argparse CLI interface and hook the new click-based CLI interface into the testsuite somehow
• actually implement the heatmap option effects (though this can probably be handled separately, other PRs dealing with that stuff already..)
• discuss the initial set of options we want and how we want to group them into sections
• decide if the extra dependencies are worth it for the CLI improvements (probably?); if so,
  hook in the new deps where needed
• Add a little bit of basic text about the summary report before the option blocks