Update README.md: improve wording

[alliesw]

Provided a more comprehensive overview description. The current README.md is overflowing with commas, unnecessary information, and is overall worded poorly.

The entire README.md should be revised to read more comprehensively.

PR checklist

• Provide an overview of the changes you're making and explain why you're proposing them.
• Create a changelog snippet (add the CHANGELOG-missing label to this pull request in order to have a snippet generated from its title;
  or use scriv create locally and include the generated file in the pull request, see scriv).
• Include Fixes #NNN somewhere in the description and scriv changelog entry if this PR addresses an existing issue.
• If this PR is not complete, select "Create Draft Pull Request" in the pull request button's menu.
  Consider using a task list (e.g., - [ ] add tests ...) to indicate remaining to-do items.
• If you would like to list yourself as a DataLad contributor and your name is not mentioned please modify .zenodo.json file.
• Delete these instructions. :-)

Thanks for contributing!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (08315c1) 91.16% compared to head (4abd2b2) 90.59%.

Additional details and impacted files

@@            Coverage Diff             @@
##            maint    #7550      +/-   ##
==========================================
- Coverage   91.16%   90.59%   -0.57%     
==========================================
  Files         325      325              
  Lines       43440    43436       -4     
  Branches     5785        0    -5785     
==========================================
- Hits        39600    39352     -248     
- Misses       3825     4084     +259     
+ Partials       15        0      -15     

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[yarikoptic]

As a non-native English speaker it is hard for me to give adequate judgement to proposed changes. But I would like to thank you first of all for the attempt ;-)