In LMS, load OVA JS only in four OVA templates with requireJS. [TNL-693]

To avoid having OVA JS files loaded in every page of the LMS and therefore clash with edXNotes, remove their entries from ```PIPELINE_JS``` in ```common.py``` and load them instead, via requireJS, in the 4 OVA templates: ```imageannotation.html```, ```notes.html```, ```text annotation.html```, and ```videoannotation.html```.

@jimabramson, @explorerleslie Please review.

Alternatively, we can also load the OVA JS in the 4 templates by using ```PIPELINE_JS``` and defining a new group called ```ova_js```:
https://github.com/edx/edx-platform/compare/jmclaus/load_ova_js_from_templates

This runs into a problem though. The following line for example will always be executed:
https://github.com/edx/edx-platform/blob/5cc0e023103475850c6ad1d77fa0a31605f69bb9/lms/templates/videoannotation.html#L203
But in Studio, we'd like to use requireJS:
https://github.com/edx/edx-platform/blob/5cc0e023103475850c6ad1d77fa0a31605f69bb9/lms/templates/videoannotation.html#L206
Interesting! I like this idea.