Improve automated release workflow

[popematt]

Issue #, if available:

None

Description of changes:

This skips the spotless checks when the build is running as part of the "Publish Release Artifacts" workflow, and also splits up the various gradle targets of that workflow into a few different workflow steps.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 67.41%. Comparing base (3c1b6b1) to head (77bf128).
Report is 39 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #812      +/-   ##
============================================
+ Coverage     67.23%   67.41%   +0.18%     
- Complexity     5484     5521      +37     
============================================
  Files           159      160       +1     
  Lines         23025    23080      +55     
  Branches       4126     4126              
============================================
+ Hits          15481    15560      +79     
+ Misses         6262     6247      -15     
+ Partials       1282     1273       -9     

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