[meta] TLS test suite

[franziskuskiefer]

• self test (client-server)
• manual interop (e.g. openssl server + bertie client, bertie server + openssl client)
• interop framework
  • Integrate BoringSSL test suite (BoGo) #30 (not useful for interop)
  • Evaluate (and integrate) TLS-Anvil. #31 (not useful for interop)
  • https://github.com/xvzcf/tls-interop-runner #48 (not useful for interop)
  • https://github.com/tlsfuzzer/tlsfuzzer #49 (not useful for interop)
• tls test vectors (e.g. https://datatracker.ietf.org/doc/html/rfc8448)