update timeout middleware with warnings

[aldas]

update timeout middleware with warnings and add example how to implement similar functionality in handler function

[aldas]

todo: probably should mention Nginx/Apache etc similar behavior and configuration settings

[aldas]

note to self: probably should add a note that order of middlewares is important. ala if timeout was added before logger. then logger middlewares logs response info for already served requests. Or what will happen if handler is websocket?