lib: Update Link State functions to handle IPv6

lib: Update Link State functions to handle IPv6

In order to add Link State Traffic Engineering to IS-IS, Link State library
should have been updated:

- Correct Node and Edge RB Tree comparison functions to support key > 32 bits
- Change Subnet RB Tree comparison function to take into account host part of
  the prefix i.e. 10.0.0.1/24 and 10.0.0.2/24 are considered as different
- Add new function to convert IS-IS ISO system ID into Vertex or Edge key that
  take into account Endianness architecture
- Correct Vertex and Edge creation and search function accordingly
- Add extra Adjacency entries in Link State Attributes for IPv6 Segment Routing
- Update send/received and show TED functions accordingly

Signed-off-by: Olivier Dugeon <olivier.dugeon@orange.com>