Implement filtering shells

[tunacicek]

As a developer,
I want to extend the AAS API to allow filtering of shells based on their creation timestamp,
so that data consumers can retrieve only the relevant shells since their last request, ensuring efficient and resource-saving operations.

Requirements:

• Implement the timestamp filter in the API based on the documentation provided. Concept Filtering Shells
• Update relevant test cases and validate the functionality.

Useful links
admin-shell-io/aas-specs-api#176

Related issues
admin-shell-io/aas-specs-api#346
admin-shell-io/aas-specs-metamodel#484

[shijinrajbosch]

Please be informed that the 'created_date' column already exists in the Shell table as a non-null column. Therefore, this change is backward compatible.

PR #506