Fix typo in pom file

Update URLs in pom
Rename Jenkinsfile

New RELEASE tag

TextGrid Aggregator 1.4.13 can deliver plain text

The new /text endpoint can transform TEI or TEI Corpus documents to
plain utf-8 text and deliver that as single document. It uses the same
transformation that is also available in the ZIP export using
`&transform=text` for some time.