Previously, every time Heat loaded a stack - including just to get the metadata of a resource because os-collect-config is polling it - it logged at INFO level every single type mapping in the user's environment. For TripleO, in particular, there were many such mappings in the standard environment. A typical deployment of TripleO generated several Gigabytes of logs.
This patch reduces the frequency of logging environment resources by logging all environment resources (e.g those from resource plugins and the global environment) only when starting the service, and logging user-provided template resources when validating template on create/update, for only the root stack, because this passes a derived subset environment down to all children. This update also switches to using the string representation of the ResourceInfo objects, as this contains more useful information than the previous log format.