Perl XS wrapper for open62541 OPC UA library

Changes for 2.03 - 2023-08-09

• Server config method AccessControl_setLoginCheck() can be used to implement different password verification schemata. Currently OpenBSD crypt_checkpass() libc function can be used for salted and hashed passwords. It uses UA_AccessControl_setCallback() function which is not commited to open62541 yet. Warning: Semantics may change in a later version.
• Server config method AccessControl_CryptNewhash() is provided to generate such password hashes easily from Perl.
• Default accounts in open62541 with user1/password and user2/password1 can be disabled by calling server config method setAccessControl_default().
• Server config method setAccessControl_default() calls UA_AccessControl_default() to set anonymous access, certificate verification, user token policy uri, and username password list for login.
• UA_UsernamePasswordLogin is created from Perl hash with username and password.
• UA_CertificateVerification can be used as Perl object. It has method Trustlist() to set trust, issuer, and revocation lists with UA_CertificateVerification_Trustlist() function.