Propose batch from pre-constructed jobs

[hkethi002]

Fixes #940

Changes

• New Endpoint: POST /batch/jobs with a list of jobs, jobs: [{...}, {...}, ...], in the payload

• The job maps from the payload are stored in batch.proposal.preconstructed_jobs in mongo

• Jobs are validated on proposal for gear manifest, inputs, config, and permissions

• On batch run, the jobs then follow the normal job cycle

  Review Checklist

• Tests were added to cover all code changes

• Documentation was added / updated

• Code and tests follow standards in CONTRIBUTING.md

[codecov-io]

Codecov Report

Merging #1069 into master will increase coverage by 0.04%. The diff coverage is 97.5%.

@@            Coverage Diff             @@
##           master    #1069      +/-   ##
==========================================
+ Coverage    90.8%   90.85%   +0.04%     
==========================================
  Files          50       50              
  Lines        7029     7063      +34     
==========================================
+ Hits         6383     6417      +34     
  Misses        646      646

[AshleyAncona]

@nagem and @kofalt this is ready for review

[kofalt]

Notably, this PR is a lot easier to read when using w=1.