CI: Create and push docker images

[Zomzog]

Hi,

First thanks for your application, it helps me a lot!

I create this PR because I deploy it to a local Kubernetes server so I need a docker image of this.
I've created a distroless version of the docker image because it's more secure and smaller (from ~300M to ~80Mb).

This PR will require an access token for the docker hub, after login-in you can create it here.

After you must add them to secret variables in the github settings.

And it should work and solve #274

[Pugmatt]

Thank you for taking the time to set all this up, really great stuff. Gave it a test run with the latest release, and works like a charm.

The newly released BedrockConnect version also allows the settings to now also be configured through environment variables or config file, which should hopefully make configuring the software easier for Docker / Kube setups.