ziafazal/api-add-filters-to-users-api

@mattdrayer @martynjames added `course` filter to user groups api and modified `type` filter to accept multiple values
`/server/users/{user_id}/groups/?type=series,seriesX&course=slashes%3AMITx%2B999%2BTEST_COURSE``
It would support MCKIN-1985