Revise technical design doc to reflect 1.0 functionality

[rlskoeser]

Associated Issue(s): resolves #328

Changes in this PR

• Revise & simplify technical design doc to match 1.0 functionality
  • updated version of system architecture diagram
  • updated data tables to match fields used by the code
  • simplified, consolidated, removed extraneous or developer-specific content that is no longer needed
• added section describing default directory structure

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.65%. Comparing base (bb51faf) to head (6cff9d6).
⚠️ Report is 1 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #338   +/-   ##
========================================
  Coverage    99.65%   99.65%           
========================================
  Files           32       32           
  Lines         2336     2336           
  Branches       101      101           
========================================
  Hits          2328     2328           
  Misses           1        1           
  Partials         7        7           

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