testing/frog: new aports

This MR contains the Natural Language Processing (NLP) and machine learning software stack developed at the Centre of Language and Speech technology , Radboud University Nijmegen (and prior to that Tilburg University), and currently maintained (by me) from KNAW Humanities Cluster (the Netherlands). This is all scientific open source software (GPLv3) which I'd like to bring to Alpine Linux. The software was mostly funded in the scope the the CLARIAH project and predecessors CLARIN-NL.

Frog, ucto and timbl are CLI-tools that are most directly relevant for end-users/researchers.

Note: libtar is a 3rd party dependency. It wasn't packaged for Alpine yet so I included it.