Code cleanup of extended operations.


ExtendedOperationHandler.java:
Added ctor ExtendedOperationHandler(Set<String> supportedControlOIDs).
Implemented initializeExtendedOperationHandler() and finalizeExtendedOperationHandler() by moving common code here from subclasses impls.
Made registerControlsAndFeatures() and deregisterControlsAndFeatures() private.
Added overridable method getExtendedOperationOID().

GetSymmetricKeyExtendedOperation.java, CancelExtendedOperation.java, GetConnectionIDExtendedOperation.java, PasswordModifyExtendedOperation.java, PasswordPolicyStateExtendedOperation.java, StartTLSExtendedOperation.java, WhoAmIExtendedOperation.java:
Removed getSupportedControls() + supportedControlOIDs field member where present - superseded by the superclass ones.
In initializeExtendedOperationHandler(), delegated to superclass method. Cannot replace it fully because method signatures do not match.
Removed finalizeExtendedOperationHandler(), rely on superclass implementation where possible.
Implemented getExtendedOperationOIDI() and getExtendedOperationName() sometimes.
Code cleanup.