Remove RequestLogger Filter and TimerFilter

With the introduction of standardized HTTP Request Logging in NIFI-9291, the custom RequestLogger and TimerFilter classes should be removed.

The RequestLogger filter logs informational messages for unencrypted HTTP access attempts. With the default NiFi configuration enabling HTTPS, this use case is no longer common, and HTTP Request Logging in nifi-request.log can provide the same information plus additional request details.

The TimerFilter runs for every HTTP request and writes debug log messages that include millisecond timing information as well as the contents of X-RequestTransactionId and X-Request-Replicated HTTP headers. This debug logging is not enabled in the default Logback configuration. The same header and request timing information can be captured using a custom nifi.web.request.log.format with the following message format:

%{X-RequestTransactionId}i %{X-Request-Replicated}i %T