improved some functions to deal with domains and ranges that are a unionOf, and added functions to print categories of saref:Function and of saref:Task

added diagrams for Waste, Collection and Treatment modules in new tabs, as well as a symbology legend for the diagrams I added

closes #4

Closes #4

See merge request !7

Closes issue 13

Closes #13

See merge request !8

closes #7 and #17

Closes #7 and #17

See merge request !13