Fix Backend Interfaces 1.1 support, authenticate with NSID

[johanstokking]

Summary

Groundwork for #4847

Changes

• Add proper LoRaWAN Backend Interfaces 1.1 support for interacting with a Join Server by using the mandatory SenderNSID (EUI64) from config
• Support HTTP basic authentication with Join Servers
• Remove obsolete DNS lookup for JS
• Simplify pkg/interop client implementation and removed generated YAML in testing

Testing

CI and local integration testing with new The Things Join Server

Regressions

None expected

Checklist

This is a draft, still needs documentation and changelog

• Scope: The referenced issue is addressed, there are no unrelated changes.
• Compatibility: The changes are backwards compatible with existing API, storage, configuration and CLI, according to the compatibility commitments in README.md for the chosen target branch.
• Documentation: Relevant documentation is added or updated.
• Changelog: Significant features, behavior changes, deprecations and fixes are added to CHANGELOG.md.
• Commits: Commit messages follow guidelines in CONTRIBUTING.md, there are no fixup commits left.

[johanstokking]

@adriansmares no functional changes since your last review.

I'll wait with merging until the changelog in v3.18 is up to date.

[KrishnaIyer]

Implementation looks pretty good. I'm testing now so I'll get back if there's anything.

[KrishnaIyer]

Also integration tests successful.