heat engine : Add validation of stack names

Add regex validation of stack names, aligns us with stack names
allowed by AWS, with the addition of "." and "_" characters

fixes bug 1103447

Change-Id: I8fab0d3ad03379dfc2a18dc016e66ca8fee6cc86
heat templates : Update for F18

Remove F16 as it's EOL, update with F18 as it's the current
version.  Leave the default as F17 for now in all except the
Openshift templates (because Openshift doesn't work on F17,
although these templates are currently broken anyway..)

fixes bug 1154121

Change-Id: Ia95e6bfb4a15e355dfb0051d57f5b70a408551c6
Merge "heat templates : Update for F18"
Merge "heat engine : Add validation of stack names"