Clean up old CI testing framework (in main), then merge to feature/capgen

[climbfuji]

Description

I am seeing a few files in main and feature/capgen that are associated with previous CI testing framework implementations, e.g. .travis.yml. We should clean up and remove whatever isn't used any more in main, and then update feature/capgen from main (which is generally a good idea to do from time to time).

Steps to Reproduce

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Additional Context

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Output

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[climbfuji]

Most of this was done in previous PRs and the merge from feature/capgen to main. The remaining piece of removing .travis.yml will be done as part of #612