Support for TLS ECH (Encrypted Client Hello)

[wiktor-k]

Title: Add support for accepting encrypted Client Hellos

Description:
SNI information in the initial TLS handshake is not encrypted by default, ECH solves this issue.

Browsers support RFC 9849 - TLS Encrypted Client Hello already for some time: Firefox since version 118, Chrome since 117.

Some servers also support ECH, e.g. Nginx and haproxy.

[optional Relevant Links:]

Any extra documentation required to understand the issue.

• Understand Encrypted Client Hello (ECH)
• Encrypted Client Hello - the last puzzle piece to privacy

[adisuissa]

cc @ggreenway @RyanTheOptimist

[github-actions]

This issue has been automatically marked as stale because it has not had activity in the last 30 days. It will be closed in the next 7 days unless it is tagged "help wanted" or "no stalebot" or other activity occurs. Thank you for your contributions.

[wiktor-k]

Not stale

[github-actions]

This issue has been automatically marked as stale because it has not had activity in the last 30 days. It will be closed in the next 7 days unless it is tagged "help wanted" or "no stalebot" or other activity occurs. Thank you for your contributions.

[mostpinkest]

Not stale