bug 4862 - Change label of Browse by subject or author to Authority search

bug 4862 - Change label of Browse by subject or author to Authority search

Replicate:
Load the OPAC
You should see "Browse by Subject or Author right below the search box

To test:
Apply patch
Load the OPAC
You should see "Authority search" where "Browse by Subject or Author" was .

Signed-off-by: Mason James <mtj@kohaaloha.com>
Amended patch: change strings in opac-authorities-home.tt

Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>