Prepare poms for release

[miszobi]

This:

• sets up maven-release-plugin to release to central through Sonatype's OSS repository hosting
• adds metadata to the poms required for releasing to central
• configures signing the released artifacts using gpg and maven-gpg-plugin
• cleans up some duplicated properties/unneded dependencies

One-time setup before releasing

• Set up an account with Sonatype as documented here
• Make sure the ticket is marked as Resolved before proceeding
• Add the account credentials to your $HOME/.m2/settings.xml:

<settings>
...
   <servers>
     <server>
       <id>sonatype-nexus-staging</id>
       <username>sonatype-nexus-userid</username>
       <password>sonatype-nexus-password</password>
     </server>
     <server>
       <id> sonatype-nexus-snapshots</id>
       <username>sonatype-nexus-userid</username>
       <password>sonatype-nexus-password</password>
     </server>
...

• install gpg, generate a key-pair (gpg --gen-key, then gpg2 --list-keys to get your key id), send your public key to the keyserver (gpg2 --keyserver hkp://pool.sks-keyservers.net --send-keys KEYID) - see detailed instructions

Doing the release

Run mvn clean release:prepare release:perform.

• This will ask for the version number to be released, and the next development version number, defaults should be fine
• it'll ask a number of times for your gpg key passphrase to sign all the artifacts
• tag the release in git and increment the version number
• deploy the artifacts to sonatype

Artifacts will be deployed to the sonatype staging area. Go to https://oss.sonatype.org/ and follow the instructions to locate and close the staging repository for the release, to release the artifacts to central.

[miszobi]

Inherited from parent, were duplicated here.

[pitbulk]

Thanks for this contribution. I will follow your steps.

[pitbulk]

I created the Jira account and the project: https://issues.sonatype.org/browse/OSSRH-24376

[pitbulk]

The ticket is now marked as "RESOLVED" but before release I want to provide to the toolkit some documentation