Dockerizes meesign-server, adds release to Dockerhub.

[KristianMika]

Release types

Stable release

The release is triggered upon a tag creation. The component is built and pushed into Dockerhub with the specified tag and latest tags.

Nightly release

This release is triggered every midnight only in the upstream repository (not forks). The component is built and pushed into Dockerhub with the nightly tag.

Note: As we are using the GitHub actions scheduling feature, it can happen that some nightly releases will be delayed or skipped.

Usage notes

As the MeesignHelper is not configurable and requires the jar archive (copied at the build time) and the private key + certificate (mapped at runtime) in the current folder, the usage requires mapping both files (key and cert) separately, i.e. --volume pwd/server-key.pem:/meesign/server-key.pem --volume pwd/server-cert.pem:/meesign/server-cert.pem. One of the options is to instruct MeesignHelper to search for the files in a specified directory, e.g., ./certs/.

Before merging TODO

• Set the DOCKERHUB_TOKEN repository secret
• check the account (crocs-muni) and project name (meesign) match the created Dockerhub names
• consider setting up a log level in Dockerfile