Bug 27498: Add a link for the Hold Ratios to Acquisitions home page

Bug 27498: Add a link for the Hold Ratios to Acquisitions home page

This patch adds a link to the hold ratios report in the Acquisitions
sidebar menu under the "reports" heading.

To test, apply the patch and go to Acquisitions. The link to the hold
ratios report should be there and it should work correctly.

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Amit Gupta <amitddng135@gmail.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>