Fix for htmlbooks

Htmlbooks were not updated in https://github.com/edx/edx-platform/pull/3744/files. This PR makes the relevant changes:
1. Adds tinymce.js to the template since it is no longer being included globally.
2. Tokens are no longer fetched via get calls but included in the template in other places where the annotation tool is used and the url to fetch them has been removed (see above PR). So fixes it for this case.
3. Passes storage_url as a token. At the moment there is a hardcoded value which is no longer in service.
4. Right now the tinymce editor is not working in the annotation popup.

Fixes for the first three are needed for the htmlbooks to be at least browsable/readable. Still trying to figure out the cause of 4 but want to get these fixes in for now.

We will verify this on stage manually for now. Tests are in progress.