Initializes the hook configurators. The following steps are used to initialize the hook configurators.
1. Get a list of hook configurators from all hook configurators properties files on the classpath,
add this list to the overall list of hook configurators, remove duplicates.
2. Get a list of hook configurators from the ("osgi.hook.configurators.include") system property
and add this list to the overall list of hook configurators, remove duplicates.
3. Get a list of hook configurators from the ("osgi.hook.configurators.exclude") system property
and remove this list from the overall list of hook configurators.
4. Load each hook configurator class, create a new instance, then call the
HookConfigurator#addHooks(HookRegistry) method
5. Set this HookRegistry object to read only to prevent any other hooks from being added.