Breaking out heat monitoring

Now that we have the heat.enabled feature flag we also need to be sure we
only enable heat checks when heat is present.
Only install the heat client when heat.enabled

We dont need the heat client unless we actually have heat.
Check endpoint is defined

Looks like ther are scenarios where ansible gets unhappy about dict keys
not being set, even if not being used. So, instead of leaving keys
undefined, also allow one to set them false.
Only heat-manage db_sync when heat.enabled

Cant run heat-manage with a tool that doesnt exist.
Merge pull request #337 from blueboxgroup/heatcleanup

Heatcleanup