feat: update supported TLS ciphers and curves
feat: update supported TLS ciphers and curves

- Remove NIST P curves as they are not safe according to https://safecurves.cr.yp.to/.
  Only X25519 is now supported but according to https://en.wikipedia.org/wiki/Comparison_of_TLS_implementations#Supported_elliptic_curves
  all relevant implementations support this curve.
- Remove CBC ciphers, add ChaCha20-Poly1305 ciphers, add other GCM ciphers

credentials/irmago