update rotatelogs docs to reflect the support for -l/UTC-offset

with size-based rotation

move examples to a formal section in the customary order

add an example of logging at midnight with the date in the
filename


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@596830 13f79535-47bb-0310-9956-ffa450edef68