4.x: Fail more gracefully for HTTP/1.0

[tomas-langer]

Currently we:

• Log FINE io.helidon.webserver.http1.Http1Connection: io.helidon.http.RequestException: Invalid protocol and/or version
• Return 400 Bad Request

Event though this is functionally correct, as we do not support HTTP/1.0, it may be better to do a bit more:

• Log (still in FINE, must not use any level above it): "Unsupported protocol: HTTP/1.0" - make sure the text taken from the request is clean, as it is user provided, so it may contain attempts to attack us (there are already tools for that, see header validation)
• Return 505 HTTP Version Not Supported for the case we get any other version than 1.1 for HTTP, sending a descriptive message in the entity (i.e. HTTP/1.0 is not supported, please use HTTP/1.1 or something similar) (again make sure the returned value is a valid string)

This is a follow up for #9604