Add support for running post-processing on GCP Cloud Run

[lathanh]

Some notes:

• This is a rough first pass; there's a lot of opportunity for cleanup, but wanted to get some feedback before doing that. That said, all feedback is welcome (e.g., even on obvious cleanup opportunities)
• It hasn't been rebased onto 'gcp' yet, so the diff currently shows some recent changes on 'gcp' (currently e449578 Fix documentation cross-reference)

[github-actions]

File	Coverage
All files	85%	✅
base.py	90%	✅
eagle.py	77%	✅
exc.py	57%	✅
local.py	70%	✅
postprocessing.py	84%	✅
utils.py	91%	✅
cloud/docker_base.py	0%	❌
sampler/base.py	79%	✅
sampler/downselect.py	33%	✅
sampler/precomputed.py	93%	✅
sampler/residential_quota.py	61%	✅
test/test_docker.py	33%	✅
test/test_validation.py	97%	✅
workflow_generator/base.py	90%	✅
workflow_generator/commercial.py	53%	✅
workflow_generator/residential_hpxml.py	86%	✅

Minimum allowed coverage is 33%

Generated by 🐒 cobertura-action against a422f63

[nweires]

High level, this looks good to me!

Hopefully we can refactor some of the shared setup code nicely so starting each batch job is concise and easy to read.

[lathanh]

This now uses Cloud Run instead of Batch. It's ready for official review except that I need merge in 'gcp'

[lathanh]

Hopefully we can refactor some of the shared setup code nicely so starting each batch job is concise and easy to read.

It now uses Cloud Run, so there's no longer as much opportunity/need to share code.

[nweires]

The Cloud Run job itself looks good - just left some questions about configuration options and usability.