Bug 22464: Pass forward parameters

Bug 22464: Pass forward parameters

This patch ensures that parameters that are present are passed forward
when accepting the copyright notice.

Test plan:

- Clone the latest version of the FreeForm backend from:
  https://github.com/PTFS-Europe/koha-ill-freeform
- Ensure the ILLModuleCopyrightClearance syspref is populated
- Create an OpenURL in order to pre-populate the FreeForm form, a suitable URL would be:

<your_koha_instance>/cgi-bin/koha/opac-illrequests.pl?openurl=true&backend=FreeForm&method=create&opac=1&atitle=Theater%20careers.%20%5Belectronic%20resource%5D%20%3A%20a%20realistic%20guide.&aulast=Donahue%2C%20Tim&date=2012&genre=article&isbn=978123123123&issn=1234-5678&issue=34&pages=12-34&sid=EBSCO%3AAthlone%20Institute%20of%20Technology%3Aait.101326&title=article%20title%20here&volume=12

- Log in
- Accept the copyright notice
=> TEST: Observe that the FreeForm form is pre-filled with the metadata
supplied in the OpenURL

Signed-off-by: Liz Rea <wizzyrea@gmail.com>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>