PE: Rewrite clone allocation to reuse more code and be simpler to understand

• Performs less magic in the clone allocation stage
• Allows specific instances to be colocated with other resources
• Detects and escalates attempts to allocate resource components separately from their containers
• Split master/slave allocation from action creation
• Perform action creation as an independant step
• Update the regression tests

Mercurial revision: 38d87d2e95b708c88f19f1323c8459f14224564e