Bug 30423: Convert authority merge page tabs to Bootstrap

Bug 30423: Convert authority merge page tabs to Bootstrap

This patch updates the authority merge page to use Bootstrap tabs
instead of jQueryUI.

To test, apply the patch go to Authorities in the staff interface.

- Perform an authority search which will return more than one
  authority record.
- On the results page, click Actions -> Merge for two authority
  records.
- Click "Next" after selecting a merge reference.
- On the next page you should see two tabs under "Source records."
  Confirm that they work correctly.
- Confirm that tag and subfield selection still works correctly.

Signed-off-by: Séverine Queune <severine.queune@bulac.fr>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>