Hst Container Component Items must not have their parameter values overridden by ancestor components

I want to change some behavior of how hst component container items and parameter (pageSize, color, etc) of them are handled. I am quite sure this won't effect any existing project out there at this moment. However, if we don't do this now, then it might become harder in the future.

Rationale: Hst component container items should be in all cases self-contained : They must be pluggable by something like a forge component. They should not be dependent on ancestor components

Currently, if any ancestor component defines 'pageSize' as parameter name, then, all the child components, including the containeritemcomponents get this pageSize parameter (and value). If the pageSize parameter is already present on the containeritemcomponent, the containeritemcomponent gets its pageSize overridden. This is very much undesirable: This way, you cannot change the pageSize variable on the containeritemcomponent any more.

I'll change this behavior with this check in to have the containeritemcomponent not have its parametervalues overridden by ancestor items: It only also gets the parameter values from ancestors for parameter names that it does not yet have