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 two first of the batch of new convenience operations.
What is missing is the mongo part (see '#if 0' in serviceRoutines).

The reason for it is that the 'tag' function called has two parameters, one for xml-tag and another one for json-tag. Then, is that reason enough?

This is is a priority for this PR, so I'll add a FIXME about it.