Technical Debt: Change quartz serialized blob into jcr properties

During an upgrade you can run into the problem that the schedule information is stored as a quartz serialized blob.
The reference to the document inside the blob is not a regular document reference, this also causes issues because the reference is not updated.

This can be solved by changing the blob into jcr properties. This blob is contained in the hipposched:job and the hipposched:trigger types as property hipposched:data.

Additionally the super type hippo:request may contain a field document which is not a reference, nor is named hippo:docbase, but is a reference to a document variant, so should probably become a reference too (since it is not a reference to a handle).