Provide ASP libraries at maven central

[de-jcup]

Situation

Because of the bintray sundown the asp libraries are no longer available as a gradle or maven dependency.

Wanted

ASP shall be available as a gradle or maven dependency.

Solution

Provide a deployment to maven cenral

[de-jcup]

Was already done with #30
and is already available - see https://mvnrepository.com/artifact/de.jcup.asp/asp-server-asciidoctorj-launcher/1.3.1

So usage in gradle is pretty simple:

// https://mvnrepository.com/artifact/de.jcup.asp/asp-server-asciidoctorj-launcher
implementation group: 'de.jcup.asp', name: 'asp-server-asciidoctorj-launcher', version: '1.3.1'