Add Global Configuration for Source and Kustomization

[Lappihuan]

How to categorize this issue?
/area usability
/kind enhancement

What would you like to be added:
We propose the addition of a Global Configuration feature, similar to the Configuration used by other extensions. This feature would allow operators to set up default configurations that are automatically applied to every new Shoot upon creation. Additionally, the configuration could optionally be scoped to specific Seeds or other selectors.

Why is this needed:
Implementing this feature would enable operators to define a base set of tools and configurations for every Shoot managed by Gardener. This would streamline the setup process and ensure consistency across all Shoots.