Use upstream proxyproto.HeaderProxyFromAddrs
Add support for wildcard server names in frontend directives
This adds support for matching incoming TLS connections to the
corresponding frontend when the frontend has a wildcard server name.
This does not add support for generating wildcard certificates from
Let's Encrypt, which requires DNS challenges.
Store certificates in /var/lib/tlstunnel by default
Move back directive processing to tlstunnel package
Move executable to cmd/tlstunnel
This allows us to expose the toplevel tlstunnel package.
Add support for the PROXY protocol
Don't add empty strings to list of managed certificates
Allow to route to different backend depending on SNI
Implement basic TCP proxy