switched from portray back to pdoc3 and extended the api documentation

Author: ThomasSteinbach

README.adoc

@@ -3,7 +3,7 @@
 
 A Python Library for creating dynamic pipelines for Gitlab CI.
 
-https://dbsystel.github.io/gitlab-ci-python-library/user/index.html[User Documentation] | https://dbsystel.github.io/gitlab-ci-python-library/api/index.html[API Reference]
+https://dbsystel.github.io/gitlab-ci-python-library/user/index.html[User Documentation] | https://dbsystel.github.io/gitlab-ci-python-library/api/gcip/index.html[API Reference]
 
 With the gcip and the ease and power of Python you can write Gitlab CI pipelines
 of any complexity in well manageable Python code.
@@ -57,7 +57,7 @@ Do you really want to see the link:docs/user/generated-config.yml[generated-conf
 Please read the https://dbsystel.github.io/gitlab-ci-python-library/user/index.html[User Documentation] to get a quick introduction into most
 features of the gcip.
 
-You can consult the https://dbsystel.github.io/gitlab-ci-python-library/api/index.html[API Reference] to get an overview of all classes and methods
+You can consult the https://dbsystel.github.io/gitlab-ci-python-library/api/gcip/index.html[API Reference] to get an overview of all classes and methods
 and a deeper view into their paramters.