Add warning to verify IPv6 ll address if bind fails

[corneliusclaussen]

Describe your changes

If the interface used for HLC communication does not have an IPv6 link local address, bind fails in EvseV2G. This PR adds a hint to check the ipv6 ll address if bind fails as we see this quite often in support requests on the mailing list or in zulip.

Issue ticket number and link

Checklist before requesting a review

• [X] I have performed a self-review of my code
• [ ] I have made corresponding changes to the documentation
• [ ] I read the contribution documentation and made sure that my changes meet its requirements