Component Indexing support for BDB

- only for equality matching
- only components of ASN.1 types used in an X.509 certificate can be indexed
(composite types except for RDN and DN are not supported yet)
- how to use
index [attribute name].[component reference] eq
Ex)
index userCertificate eq
index userCertificate.toBeSigned.issuer.rdnSequence eq
index userCertificate.toBeSigned.serialNumber eq
index userCertificate.toBeSigned.version eq