create a new WikidataBot class for cacheSources() and getSource()
for claimit.py, coordinate_import.py and harvest_template.py

bug: 62438

this also allows for non-Wikipedia sources
in claimit.py and coordinate_import.py
as with change I29df011b82fd8687d4c38def62d0c0ea3a1b7994

bug: 62991
Change-Id: Ic05987911f0878d42a06cf5af842134bd9d615e8
Merge "create a new WikidataBot class for cacheSources() and getSource() for claimit.py, coordinate_import.py and harvest_template.py"