Adds support to define child providers for a parent menu using a .withSubs option. This parent menu will always be displayed as an expandable menu.
When no children are visible, the expandable menus will be hidden.
- Replace god-class resolvers with a service that populates the menus from lists of injectable providers
- Static menu sections are resolved at the root route ~ `resolveStatic`
- Route-dependent menu sections can be declared in the same structure, but are resolved on-demand ~ `resolveRoute`
- More and more easily customizable
- Parts can be moved between menus, removed, replaced or extended individually
- The dependencies of each provider are independent of each other
- Order of providers determines the order of each menu → single source of truth for the order
