deserialize
Constructs a Credential from serialized data, ie. the inverse of addSerializedData.
This is required for all Credential implementations since it's used by CredentialLoader.loadCredential when loading a Document instance from disk. Since the credential is serialized by the Document and stored in DocumentStore in its serialized CBOR form, creation of a DirectAccessCredential via deserialization does not require integration with DirectAccess.
Parameters
document
the Document that the credential belongs to.
dataItem
the serialized data.