Support Monero Docker Image Build in GitHub Actions

[thormme]

Fix for #3076
This adds a GitHub action to build and upload the Monero image to Dockerhub.
This will allow the node, rpc, and cli to be run in containerized environments without having to trust random developers on the internet.

Currently this is only building the amd64 image, but more could easily be added.

Two vars/secrets will need to be added to the repository for this to function:
DOCKERHUB_USERNAME - The username for Dockerhub
DOCKERHUB_TOKEN - The Dockerhub token for the specific image

[selsta]

As far as I know the reason this was not added yet is because no one volunteered to create and maintain a Dockerhub account. For security reasons obviously this would have to be someone trusted, and I'm not sure if others want this due to the centralized structure.

[SamsungGalaxyPlayer]

You can consider publishing a GitHub Package from the monero-project GitHub organization instead:

https://docs.github.com/en/packages/learn-github-packages/introduction-to-github-packages

https://github.com/orgs/monero-project/packages

[plowsof]

On pull request to the dockerfile just push it to the official dockerhub account.... "Main" branch... Those commits.. @thormme would you consider closing this PR and making an issue for discussion instead?

[thormme]

@plowsof That's fair, I could have done more due diligence there. I've addressed your feedback.
To be clear, pull requests do not push at all push: ${{ github.event_name != 'pull_request' }}
The purpose of that pipeline is to enable testing of changes to the Dockerfile.
There is already an issue created that hasn't had much discussion in it, would you like me to make a new one or move the discussion to #3076?

[thormme]

For security reasons obviously this would have to be someone trusted, and I'm not sure if others want this due to the centralized structure.

I had a feeling that was one reason it hadn't happened. But the fact is that there are images already on Dockerhub built and maintained by random netizens, so not having an official one just makes it more likely that someone will use one that is malicious.

It should be possible to generate and serve hashes of the built images so that people could verify the identity of the images, if people don't want to trust Dockerhub.

[thormme]

You can consider publishing a GitHub Package from the monero-project GitHub organization instead:

I have set this up many times and would happily do that instead or in addition depending on what the maintainers want.

[thormme]

@selsta Would you prefer I configure this to push the image to ghcr.io?