`network_tools.py` cleaning before GVA introduction: - [x] #226: Get rid of `ipaddress` dependency - [x] !186: Delete no longer used `parse_endpoint()`, `parse_endpoints()`, `check_port()`, `check_ip()`, `endpoint_type()` - [x] Delete `check_port()` in favour of of DuniterPy's port check in the regex - [x] Delete `best_endpoint_address()` in favour of DuniterPy's `connection_handler` which choose in priority `domain`, `ipv6`, then `ipv4`.