Implement data types from RFC 8044

[MikhailMS]

There are number of data types outlined in RFC 8044 and while some of them already implemented and handled by current implementation, some are still missing

Implemented:

• text
• integer
• time
• ipv4addr
• Iipv6addr
• ipv6prefix
• string - implemented in #14
• concat - implemented in #14
• ifid - implemented in #14
• ipv4prefix - implemented in #14
• integer64 - implemented in #14

Missing:

• enum
• tlv
• vsa
• extended
• long-extended
• evs

[MikhailMS]

While #14 added definition of some new data types from RFC 8044, it forgot to update verify_original_value() & restore functions: original_string_value() && original_integer_value(), meaning that values in RADIUS packet cannot be verified or restored after packet is received by Server or Client

Thus I created #22 issues to track that work