fix: missing endpoint to delete terminated contract negotiations

[bscholtes1A]

Bug Report

Describe the Bug

Currently the connector does not provide any endpoint enabling to remove terminated contract negotiations, as described in the DSP specification: https://docs.internationaldataspaces.org/ids-knowledgebase/dataspace-protocol/contract-negotiation/contract.negotiation.protocol#id-2.6-contract-negotiation-termination-message

Expected Behavior

A delete endpoint should be available.

Observed Behavior

No delete endpoint is available.

Steps to Reproduce

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2. Click on '....'
3. Scroll down to '....'
4. See error

Context Information

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• Used version [e.g. EDC v1.0.0]
• OS: [e.g. iOS, Windows]
• ...

Detailed Description

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Possible Implementation

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[ndr-brt]

it seems more of a missing feature than a bug, wdyt?