Add OSprofiler integration into Heat

This adds builtin rpc and db traces to Heat, as well as
some toplevel stack methods to aid in reading the output.

A 'profiler' config group is added to enable profiling.

Change-Id: Ie5c1c8f1931f59e4d4bcf1ec3b791f55984eb6d2
Closes-bug: #1363782
Merge "Add OSprofiler integration into Heat"