Adds Pagination on Backend

[FriedJannik]

This PR changes the pagination logic to leverage MongoDB for page calculation rather than performing it in-memory. This reduces memory overhead and improves query performance, especially with larger datasets.

[Copilot]

Pull Request Overview

This PR migrates pagination logic from in-memory processing to database-level operations in MongoDB, improving performance and reducing memory overhead for larger datasets. The changes implement cursor-based pagination directly in MongoDB aggregation queries while maintaining backward compatibility with in-memory backends.

• Adds new getSubmodels() and getShells() methods to backend interfaces for paginated retrieval
• Implements MongoDB-native pagination using aggregation pipelines with cursor and limit operations
• Refactors repository classes to delegate pagination to backend implementations

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
SubmodelOperations.java	Adds interface method for paginated submodel retrieval
MongoDbSubmodelOperations.java	Implements MongoDB-based pagination for submodels with aggregation pipeline
InMemorySubmodelBackend.java	Implements in-memory pagination fallback for submodels
CrudSubmodelRepository.java	Delegates pagination to backend implementation
AasOperations.java	Adds interface method for paginated AAS retrieval
MongoDBAasOperations.java	Implements MongoDB-based pagination for AAS with refactored filtering
InMemoryAasBackend.java	Implements in-memory pagination fallback for AAS
CrudAasRepository.java	Delegates pagination to backend implementation

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