Parse the registry.yml file just once per RegistryManager

[jonasarts]

Currently, the registry.yml file is parsed per registry key read request. This is very bad behavior as parsing the yml multiple times is a unnecessary overhead.

Change the behavior to parse the registry.yml file just once (and keep it memory during processing) when the RegistryManager instance is created and the registry.yml file is present.

[jonasarts]

The registry.yml file is now parsed during the construction of the RegistryManager. This will give a much better performance on reading multiple keys.