Bug 21513: Add a 'Cancel' button to the authority editor and remove duplicate 'Save...

Bug 21513: Add a 'Cancel' button to the authority editor and remove duplicate 'Save' button

The authority editor (authorities/authorities.pl) does not have
a 'Cancel' button. Also, it has two 'Save' buttons.

This patch fixes that by:
a) adding a 'Cancel' button to the floating toolbar at the top
b) removing the 'Save' button from the bottom of the page

Test plan:
1) Go to Home > Authorities and launch the authority editor by
   clicking on 'New authority'. Notice how the editor doesn't
   have a 'Cancel' button. Also notice the two 'Save' buttons.
2) Apply the patch.
3) Re-launch the authority editor, and hit cancel; you should
   be taken back to Home > Authorities.
4) Edit an existing authority, and hit cancel; you should be
   taken back to the details page for the authority you chose.
5) Edit an authority as new (duplicate), and hit cancel; you
   should be taken back to Home > Authorities (this behaviour
   is mimicking the bibliographic editor: when duplicating a
   biblio the 'Cancel' button will take you back to Home >
   Cataloging).

Signed-off-by: Michal Denar <black23@gmail.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
(cherry picked from commit 2cffe3a574e14d5f35ce7b1d9ffe28a153dcb37e)
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
(cherry picked from commit 81ceef6b8410988dbf14ae0db3dfac64ae084fc9)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>