Make explorer registration order meaningful

After changes for NXP-29489, it appears that registration order set on components is not the relevant one.

Components are registered in a given order, but it is not taken into account correctly by explorer (should be asking for resolved components to the component manager, not all components).

Linking to NXP-28948 as pending components, components in error, etc.. are currently taken into account while they would not be if we considered only resolved components.

The relevant orders might actually be more complex to represent, as a given component can register its extensions "lazily" (waiting for target extension point to be present, or a requirement to be resolved).

Current sort on registrations, taking Component#getApplicationStartedOrder, is handled only after components activation (after registration of contributions), and before calling the components #start method.

Note: the component manager also uses watches, for loggin purposes: it would be useful to extract them for rendering and make it possible to notice deployment latency issues.