Bug 17416 - Move javascript in doc-head-close.inc into a separate include

Bug 17416 - Move javascript in doc-head-close.inc into a separate include

In order to prepare to move staff client javascript assets into the
footer, this patch creates a new include file containing all <script>
content. This change should have no visible effect on how pages are
generated.

To test, apply the patch and view various pages in the staff client
(ciruclation, preferences, etc) to confirm that JavaScript is working
correctly.

Signed-off-by: Claire Gravely <claire_gravely@hotmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>