Add diagram to os-collect-config README.rst

Pictures are worth 1000 words. True story.

Change-Id: Ibd2048d9e61bfab6ddf0e6d663b2bbc2f0ff20c1
Updated from global requirements

Change-Id: Ie7556c4504e4de5f696c8b147cf4ee9dfd44f64e
Merge "Updated from global requirements"
Add collector for heat API resource metadata

This collector uses keystoneclient and heatclient to poll for the
configured resource metadata.

Changes were required to test_collect to allow collectors which needed
to fake something other than requests.

Change-Id: I3e93fe38b15f71193a4c024b24e6260d6adcf1b3
Restore 'deployments' key to cfn Metadata

In recent changes support was added to explode the deployment key into
multiple json files for merging by os-apply-config. But this breaks
other users who want direct access to the full deployments structure.

There seems to be no real reason to delete the key other than tidiness,
so we will stop deleting it from the main cfn structure.

Change-Id: Icf9479376e32c3ad8f9be29359e6100c1aeda2a5
Closes-Bug: #1299110