Removal of FlowView component from Studio Components

FlowView QML component did not get productized as such. There is still potential in the component but as there are no investments on it currently, we are writing it off.

Studio Components 'dev' branch won't be having the FlowView QML type anymore, but the component is stored in branch/repo in Qt Labs if someone wants to use it on their own.

Documentation must be screened so now references to FlowView exists in the documentation.