Adding support for a basic selector list on the Redux state scheme.

[NeaSTDL]

The following improvements have been done to this utility in this deliverable:

• Added new selectedIds list to Redux state to keep a selection of entities from each specific store.
• Added new actionCreators for addSelected and removeSelected operation types.
• Added a new selector allSelected to fetch entities listed in selectedIds list.
• Improved byIdentifier selector to return a factory function instead of a unique instance for better memoization.
• Added /lib/constants directory to keep useful values and share on the modules.
• Added testing for all the different enhancements of this deliverable.