Build library on npm postinstall

[christophziegler]

Currently, the scripts in directory /dist are built from the sources using the typscript compiler tsc and checked into the git repository. This is considered to be a bad style. For one it creates unnecessary overhead (memory + files to track). Much more important, it is not obvious if the files in /dist correspond to the current development status of the sources -- no single source of truth. Actually, the files in /dist should be built after the installation via npm at the user's site, for example by a postinstall script defined in the package.json. However, this approach could not be implemented successfully so far. In consuming services, errors were encountered during build of the docker images when npm attempted to resolve the dependencies or to build the scripts. This behaviour may resolve if the depencies are contained in a public repository.