WFLY-2229 Add support for PKCS12 Keystores in security realms

I added support for other keystore types than JKS in Security Realms. The result has been achieved by additional parameter "keystore-type" in keystore configuration node. Any keystore type can be used which is supported by java.security.KeyStore object (is compatible with Java Cryptography Architecture
Standard Algorithm Name Documentation).

As I've found out, configuration model will be completely rebuilt in Wildfly 9 and will consist this functionallity, but I think it will be nice if pkcs12 format will be supported yet by 8.