ILL: prepare module for renaming & re-organizing.

* Koha/ILL.pm: will be obsolete; deleted.
* Koha/ILL/AbstractILL.pm: prepare for changes.
* Koha/ILL/Config.pm: prepare for changes.
* Koha/ILL/Record.pm: prepare for changes.
* Koha/ILL/Request.pm: prepare for changes.
* Koha/ILL/Requests.pm: prepare for changes.
* Koha/ILL/Service.pm: prepare for changes.
* Koha/ILL/Status.pm: prepare for changes.
* Koha/Service/ILL.pm: prepare for changes.
* ill/ill-requests.pl: prepare for changes.
* members/illrequests.pl: prepare for changes.  In this case this
  involves removing the summary from the parameters for the template.
  We will need to fix this.
ILL: rename and move step 1.

* Koha/ILL/AbstractILL.pm: renamed to `Koha/ILLRequest/AbstractILL.pm'.
* Koha/ILL/Config.pm: renamed to `Koha/ILLRequest/Config.pm'.
* Koha/ILL/Record.pm: renamed to `Koha/ILLRequest/Record.pm'.
* Koha/ILL/Request.pm: renamed to `Koha/ILLRequest/Request.pm'.
* Koha/ILL/Requests.pm: renamed to `Koha/ILLRequest/Requests.pm'.
* Koha/ILL/Service.pm: renamed to `Koha/ILLRequest/Service.pm'.
* Koha/ILL/Status.pm: renamed to `Koha/ILLRequest/Status.pm'.
ILL: rename step 2.

* Koha/ILLRequest/Request.pm: rename to `Koha/ILLRequest.pm'.
* Koha/ILLRequest/AbstractILL.pm: rename to `Koha/ILLRequest/Abstract.pm'.
* Koha/ILLRequest/Requests.pm: rename to `Koha/ILLRequests.pm'.