Publish maven artifacts to sonatype

Please publish at least `api` and `core` artifacts to sonatype repo. Perhaps using the same credentials as https://github.com/ScorexFoundation/sigmastate-interpreter ?

Start by inspecting the repository's build configuration for the api and core artifacts and locating any existing publication settings. Compare the required Sonatype setup with the referenced sigmastate-interpreter repository, while confirming how credentials are supplied. Done means both artifacts can be published to the Sonatype repository without exposing credentials.

Written by the indexing model from the issue text.