Wrap private key and public certificate into PKCS#12 files

1) PKCS#12 files (containing private key file and the public certificate file) will be stored into the new "cert" schema
2) The PKCS#12 files will be password protected.
3) Password will not be stored in the system for increased security
4) Password will have to be provided to access PKCS#12 store private key & public certificate
(This will be done during PDF signing by end-user)