docs: Create a Use Cases Directory

[ajloria]

Fixes

Checklist

• I have made a material change to the repo (functionality, testing, spelling, grammar)
• I have read the [Contribution Guide] and my PR follows them.
• I updated my branch with the master branch.
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation about the functionality in the appropriate .md file
• I have added in line documentation to the code I modified

Short description of what this PR does:

• Fixes Issue Create a Use Cases Directory #87
• Creates Use Cases directory, READ.md in directory, and lays out a template for use cases which can be added anytime.

[SendGridDX]

All committers have signed the CLA.

[codecov]

Codecov Report

Merging #108 into master will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master     #108   +/-   ##
=========================================
  Coverage     49.28%   49.28%           
  Complexity       38       38           
=========================================
  Files             5        5           
  Lines           211      211           
  Branches         16       16           
=========================================
  Hits            104      104           
  Misses          103      103           
  Partials          4        4           

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