app directory integration

[keighrim]

This PR updates the app publish actions workflow (formerly container workflow) with integration with the prototype app-directory (https://github.com/clamsproject/apps/issues/15) . Closes #134 .

[codecov[bot]]

Codecov Report

Merging #137 (c65e234) into develop (65157d9) will not change coverage. The diff coverage is 100.00%.

@@           Coverage Diff            @@
##           develop     #137   +/-   ##
========================================
  Coverage    77.41%   77.41%           
========================================
  Files            7        7           
  Lines          580      580           
========================================
  Hits           449      449           
  Misses         131      131           

Flag	Coverage Δ
unittests	77.41% <100.00%> (ø)

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Impacted Files	Coverage Δ
clams/appmetadata/__init__.py	91.22% <100.00%> (ø)