Add ATR release download page guidance

Added guidance for ATR release download pages.

Author: dave2wave

content/pages/policies.md

@@ -7,3 +7,6 @@ We will list various proposed policies and policy changes. These will be specula
 
 1. [ASF standard for scannable secret tokens](./draft-asf-token-standard)
    - [FAQ](./draft-asf-token-standard-faq)
+2. [Release download page guidance for ATR](https://infra.apache.org/release-download-pages.html#current-and-older-releases)
+   - Provide the difference between svn dist releases and ATR releases.
+