history.createHashHistory() is being called whenever this package is
imported, which causes the URL to redirect to a hash. This is
unnecessary in cases where elements of wc-admin are used outside of a
completely controlled/routed page.
This lazy-creates the history object only when it's needed and therefore
avoids the URL redirection unless history features are in use.
* Move filter code to the navigation package
- Moves filter-related code to navigation, so it can be shared between components and the app
- Fixes spelling of “flatten”
- Update README docs with new functions
* Use `get` to prevent errors if options is not an array/is empty
* Update documentation and tests
* Move nav-utils and history to new package
* Update config to build and use new navigation package
* Update all imports to use new navigation package
* Remove unnecessary README
* Update nav-utils path
Kevin Killingsworth
Kelly Dwan