Performance improvement : Many hst model objects create needless immutable lists/maps very very often

Many object (like HstComponentConfigurationService) contains methods like

public Map<String, String> getParameters()

{ return Collections.unmodifiableMap(this.parameters); }

@Override
public Set<String> getParameterPrefixes()

{ return Collections.unmodifiableSet(parameterNamePrefixSet); }

These getters are typically called many many times per request and concurrently by multiple requests. We should replace this by returning an unmodifiable instance variable that is created only once

This is almost trivial to do