add docs from the heat wiki

updated index.rst to mimic the layout of the keystone docs
updated the structure for troubleshooting
ported howto guides from the heat wiki
ported the troubleshooting page from the heat wiki
updated the nav for the man pages and getting started
added docs for a cfn template and hot template

Change-Id: I14c1b0b6aa6ea3529c4de994851f7a798a3061bf
Merge "add docs from the heat wiki"