Refactor SignatureValidator and reduce interface headers

Refactor SignatureValidator and reduce interface headers

 * Integrate SignatureValidator and WrtSignatureValidator with checkReference param flag
 * Client doesn't need to initialize xml before use SignatureValidator. SignatureValidator initialize it internally.
 * Make SignatureValidator to static function to use it conveniently.
 * OCSPCertMgrUtil moved to certificate collection
 * Exclude some headers which used only inside of SignatureValidator
   - CertificateCollection
   - SignatureReader
   - ParserSchema
   - SaxReader
   - Base64 : use certvsc/ccert.h API or member functions in Certificate.h instead
   - CryptoHash : not used in anymore in 3.0

Change-Id: Ifde1768c51fc0eea2ad8a0e3c78b098ae46f02d3
Signed-off-by: Kyungwook Tak <k.tak@samsung.com>