Add family filter to completions

[drew2a]

This issue was created based on the comment from:

tribler/src/tribler/core/components/database/restapi/database_endpoint.py

Lines 319 to 327 in 035bab8

	async def completions(self, request):
	args = request.query
	if 'q' not in args:
	return RESTResponse({"error": "query parameter missing"}, status=HTTP_BAD_REQUEST)
	keywords = args['q'].strip().lower()
	# TODO: add XXX filtering for completion terms
	results = self.mds.get_auto_complete_terms(keywords, max_terms=5)
	return RESTResponse({"completions": results})

@qstokkink cited from #1722:

Our XXX filtering is now only half-working.

[qstokkink]

The family filter has now been removed and this issue is no longer relevant..