Bug 10592: fix display of favicon

Bug 10592: fix display of favicon

Move the favicon files for OPAC and staff so that they are not
blocked by the Apache configuration change introduced by the
patch for bug 9812.

Note that this patch makes the favicon customizable by theme,
not both theme and language.

To test, after applying the patch.

[1] Open pages in the OPAC and staff client.  Verify that the favicon
    is displayed in the usual place in your web browser.  Specific pages
    to test include

    - circulation receipts and slips
    - help
    - lists view
    - web-based self-checkout

[2] Verify that the Apache logs do not contain entries like this:

client denied by server configuration: {...}/prog/en/includes/favicon.ico

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Verified that the favicon displays correctly. Also
tried changing favicons for staff and OPAC using the
system preferences for those. This still works, where
the system preferences are correctly supported in the
templates.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>