Remove any reference to config_id from old xml config and drop schema

Fixes #72
Remove leftovers from old rt ticket handling
Remove unused validator UnusedID
Change scep PKIOperation to use datapool for transaction id

Stores the transaction id in the datapool instead of using a context
search.
Use pause if ca key is unusable during crl/cert issue
Add workflow id to cert_attributes table for renew and revoke
Change API methods to use new csr/crr attributes to fetch info

Methods get_private_key and get_workflow_for_certs use the crr/csr
workflow info stored in cert_attributes table instead of a context
search to load the requested information.
get_workflow_for_certs will now also return the CRR workflow and
issuance workflows from scep or scpers (but frontend cant consume them)
Modify crr workflow - go to success on parallel crr workflows