Add information required by Maven Central to public artifact POMs

Add information required by Maven Central to public artifact POMs

This is another step away from manual deployment towards Maven-triggered
deployment for both releases and snapshots. The 5 main POMs (matcher,
runtime, weaver, tools, installer) now contain information required by
Sonatype for Maven Central deployments according to:
https://central.sonatype.org/publish/requirements/

TODO:

  - Add corresponding 'distributionManagement' section and necessary
    release plugins for Sonatype OSS repositories to parent POM.

  - Enable Maven to also use Install plugin in order to automatically
    set release versions, commit to Git and tag releases, then upgrade
    to a new snapshot afterwards.

  - Make sure that Flatten Maven plugin does not strip off the required
    tags we just added to the POMs. It looks as if the chosen
    flattenMode=oss already retains the exact tags we need, only
    slightly reformatting (hence "uglifying") the POM. But an ugly POM
    does not block Maven Central deployments, as long as it is complete.
    So it looks as if this to-do item is already done.

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>