Issue #9980 - add additional codes for CustomRequestLog

[lachlan-roberts]

Adds the following options to the CustomRequestLog

%A                    - the Request authority (which might differ from the Host header).
%h                    - the Request scheme
%uri                  - the entire Request HttpURI (including query)
%{q}uri               - the entire Request HttpURI (excluding query)
%{attributeName}attr  - a request attribute

Let me know if you can think of better codes for these.

closes #9980