ABM3 v15.3.1 Production Model Specifications

[i-am-sijia]

This PR supersedes PR #34 and brings in model specifications from SANDAG's ABM3 production model, version v15.3.1.

The model specification changes have been manually reviewed to ensure they do not overwrite any existing Sharrow-related modifications implemented in this repository that are not present in SANDAG's production model v15.3.1.

This PR also includes a script diff_production_configs.py with instructions in the ReadMe.md that users can run in command line, to auto diff any versions of the ABM3 production model and the example model. Right now it will show many differences between the production model and the example model because the production model does not include Sharrow changes. If and when we get to the point where the two models are the same, this script will help easily identify new developments in the production model.

[i-am-sijia]

@bhargavasana I've brought in all the updates from v15.3.1 into this PR. Regarding your question about having a straightforward process to compare configs of the production model and the example model, I've added a diff_production_configs.py to auto diff the two, with instructions in the ReadMe.md. Right now it still shows many differences between the production model and the example model because the production model does not include sharrow changes. If and when we get to the point where the two models are the same, this script will help easily identify new developments in the production model.

So far, the non-sharrow test runs successfully and the sharrow test is failing. I have made some fixes in the configs for the sharrow run and it’s now failing in trip destination (close to the end!). Please see the log attached. Should I leave this to you @jpn-- at this point to make it sharrow compatible?
activitysim.log

[bhargavasana]

I don't think I have anything major at this point. I will have my staff compare outputs in the next few weeks.

[jpn--]

The changes in here are reviewed and OK. I opened a subordinate PR here: wsp-sag#2 to address the remaining issues. Rather than approve and merge this PR that is incomplete (and have a non-complete "main" branch) we can hopefully make one merge that gets this example up to speed and fully operational.