Update readme

[alexdebrie]

What did you implement:

Updates the README and adds examples, specifically:

• Removed API documentation from the README and into a section of the docs. Link.
• Added plugin examples and updated the Quick Start to point to the examples.
• Removed Plugin System from README and moved into separate docs page. We can re-add this to top-level once plugin system is more fully developed.

How did you implement it:

N/A

How can we verify it:

N/A

Todos:

• Write tests
• Write documentation
• Fix linting errors
• Make sure code coverage hasn't dropped
• Provide verification commands / resources
• Enable "Allow edits from maintainers" for this PR
• Update the messages below

Is this ready for review?: YES
Is it a breaking change?: NO

[codecov]

Codecov Report

Merging #406 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #406   +/-   ##
=======================================
  Coverage   65.13%   65.13%           
=======================================
  Files          26       26           
  Lines        1592     1592           
=======================================
  Hits         1037     1037           
  Misses        512      512           
  Partials       43       43

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[ganeshvlrk]

Looks good.