Revert "Merge pull request #840 from dimagi/mm-bulk-task"

This reverts commit ff45f9dcbd0f691d57af8221edb2037d5ac642c6, reversing
changes made to ccc3ced7def860dc11cd26c641a7e5816facfde8.
Merge pull request #872 from dimagi/revert-multimedia

Revert "Merge pull request #840 from dimagi/mm-bulk-task"