chore: add maven-publish plugin

[jeqo]

As the plugins may eventually be published for deployment or tooling that needs access to tiered data, we can start by adding maven coordinates to the project.

The initial proposal is to add modules under io.aiven.kafka:kafka-ts-plugin-* -- though open for other options.

[jeqo]

Changing proposal to io.aiven:tiered-storage-for-apache-kafka-* to keep it aligned with repo naming and any trademark issues