Add nix2container workflows for creating payjoin-service docker images

[benalleng]

This is a draft to explore the use of nix2container as our workflow docker deployment mechanism. At the moment I am hand deploying docker images to my personal docker hub when requested but ideally I don't want to do that.

If we can get this working I expect it will be our onestop shop for all things we would want to be a docker image. This should be able to close #1244 unless we feel like we also want to have a separate image for ohttp-relay and payjoin-directory before payjoin-service is completely fleshed out.

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[coveralls]

Pull Request Test Coverage Report for Build 21922060024

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 83.263%

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Totals
Change from base Build 21918191122:	0.0%
Covered Lines:	10238
Relevant Lines:	12296

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💛 - Coveralls

[spacebear21]

Thanks for starting on this! As I'm working on #1323 I realize it would be ideal for developer experience to build testing images on any PR that touches payjoin-service, in addition to the release images created when a tag/release is made.

[benalleng]

Ok i will make sure to expand when this job runs to include any payjoin-service change. Right now I have the release activity type set to published but there are a lot of options https://docs.github.com/en/actions/reference/workflows-and-actions/events-that-trigger-workflows#release though published seems to make the most sense.

[benalleng]

Trying to use a secret that was given to me but it isn't working as expected. @spacebear21 could you take a look at an org secret that we might be able to use to write packages?

[spacebear21]

What does this change achieve?

[benalleng]

The name is what .copyToRegistry tries to push to, without the explicit name the inherited name I think is just a dummy payjoin/payjoin-service-image pathname. Testing this now to confirm

[spacebear21]

utACK, merging so we can test the workflow