embedded channel performance stats

uPortal should (optionally?) embed channel performance information in its HTML output.

An administrator, developer, or helpdesk specialist should be able to "view source" when a user's layout performs poorly and glean information about which channels were problematic in that rendering.

Preceding each channel in the output would be an HTML comment indicating whether the channel content came from a cache or from a dynamic rendering and if from a dynamic rendering how long the particular channel took.

Jira issue