URL-parsing+rendering part of the first two new convops ready

### Description
This PR implements the parsing of URL plus the rendering in XML and JSON of the first (/v1/contextTypes) of the batch of new convenience operations. A second new conv op is prepared for but not terminated (/v1/contextTypes/{entityType})

What is missing is the mongo part (see '#if 0' in serviceRoutines).

This here seems a little crazy ...
Why not start the for-loop at 'offset'?
11 lines before:

    for (unsigned int ix = offset; ix < ...