Publish refactor

[mpacer]

This takes some of the lessons from #139 and applies them to the publish module.

Most notably it takes as much logic as possible out of the _publish method, making it only about speaking to s3 and nothing else.

Also, this moves a lot of the s3 string creation into the base put method & simplifies some of the logic that was happening in prepare_response.

This needed to build on #140 (since it changed the docstring), so if this is merged, that can be closed.

[codecov[bot]]

Codecov Report

Merging #141 into master will not change coverage. The diff coverage is 64.28%.

@@           Coverage Diff           @@
##           master     #141   +/-   ##
=======================================
  Coverage   74.87%   74.87%           
=======================================
  Files          10       10           
  Lines         414      414           
=======================================
  Hits          310      310           
  Misses        104      104

[codecov[bot]]

Codecov Report

Merging #141 into master will decrease coverage by 4.26%. The diff coverage is 64.28%.

@@            Coverage Diff             @@
##           master     #141      +/-   ##
==========================================
- Coverage   79.14%   74.87%   -4.27%     
==========================================
  Files          10       10              
  Lines         422      414       -8     
==========================================
- Hits          334      310      -24     
- Misses         88      104      +16

[mpacer]

for some reason the code coverage reports got messed up when I rebased on master… I'm not entirely sure why they're saying it reduces coverage… it doesn't change coverage at all

[mpacer]

Grazie!