Bulk operations in annotation list

[tanius]

In the "Annotations" section of the Open Ethnographer backend, we'd like to have bulk operations similar to how it's done in the "Codes" section. That is, there should be a checkbox before each annotation, and a list of operations that can be executed with the selected annotations. The possible bulk operations should be "Move" (implemented in #214) and "Destroy" (already implemented for individual annotations).

Ideally there should also be a "Select All" button, selecting all annotations on the current page. It should be made clear that this only selects annotations on the current page, not on other pages as well.