Refactor(module-context): Move Event Type Declarations to a Separate File

**Description:** Currently, all event type declarations for the context provider are defined at the bottom of ContextProvider.ts. To improve maintainability and separation of concerns, these event type declarations should be moved to a dedicated file (e.g., ContextProvider.events.ts or similar). This will make the main provider implementation cleaner and make it easier to manage or extend event types in the future.

**Tasks:**

- Move the declare module '@equinor/fusion-framework-module-event' block and all related event interface/type definitions to a new file.

- Ensure the new file is properly imported or referenced where needed.

- Update any documentation or references as necessary.

**Benefits:**

- Cleaner and more maintainable codebase.
- Easier to manage and extend event types.
- Improved separation of concerns.

[ContextProvider.ts](https://github.com/equinor/fusion-framework/blob/ca27af9997afd4196b6ec91b21ebdd44a5ac5084/packages/modules/context/src/ContextProvider.ts#L978)