Better way of adding an `Enabled` property on a component.

[ferafiks]

Is your feature request related to a problem? Please describe.
Stride does not provide a way to toggle entities, but it does provide a way of toggling all activable components using Entity.EnableAll.

However, there is a bit of inconsistency between Game Studio and the runtime:

• Game Studio treats all components with an Enabled property (even if manually defined) as activable (the property is placed next to the component name.
• Stride's EnableAll only works with components deriving from ActivableComponent.

Describe the solution you'd like
Introduce an IActivableComponent interface with a required Enabled property and make Game Studio and EnableAll only treat components with that interface as activable.

Describe alternatives you've considered

1. Make Game Studio only treat ActivableComponent components as activable - the problem is that ActivableComponent can't have Update or Execute, which is limiting.
2. Make EnableAll look for Enabled property - seems like it would be too computationally expensive.
3. Remove EnableAll and instruct users to just remove entities from scenes and store them in a variable - as much as I like this idea, the feature is already there

[bnwa9723]

@ferafiks I think we should unite and find ways to solve the compiler extension problem. We can propose various solutions to address this issue.