[TYPO3-core] RFC #7942: Enable UTF-8 by default

[Xavier Perseguers]

Hi,

> * The check in isConnectionUtf8 is an unnecessary over-optimization. Ask the server, if you want to
> know about the server.

I agree that I do not understand why we cannot use a configuring flag to 
know whether it's UTF8 or not. Do this magic once for an upgrade wizard 
but then do not perform any magic anymore.

Xavier