docs: Rewrite log rotation section in logs.xml

docs: Rewrite log rotation section in logs.xml

- Replace hand-rolled mv/graceful/sleep/gzip recipe with modern
  practices: rotatelogs (recommended) and system logrotate
- Add examples for time-based, size-based, and strftime-pattern rotation
- Rewrite piped logs section: tighten prose, remove redundant
  rotatelogs example, wrap highlight blocks in <example> tags
- Remove "In order to", "simply", bare "Apache" references

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1935553 13f79535-47bb-0310-9956-ffa450edef68