[REFACTOR] Remove dead code for BrowseEverything uploads from Box

[mark-dce]

RATIONALE Emory no longer supports Box for large file uploads. Therefore Box support, and correspondingly BrowseEverything can be removed from the applicaiton.

As a side benefit, some of the code being removed was not covered in the existing test suite, resulting in higher overall test coverage.

[coveralls]

coverage: 94.756% (+0.5%) from 94.221% when pulling 4e760cc55617fe60cda2bde616d4045596216696 on etd_controller_coverage into d7a7a63e912c3a8bc1dc32cbe9dfb436ffbcce29 on main.