Add termiantion endpoint for consumer and improve text (#112)

* feat: added termination endpoint for consumer

* fix: semantic separation of http codes

* fix: add line break

* Update contract.negotiation.binding.https.md

Revert changes

negotiation/contract.negotiation.binding.https.md

@@ -17,7 +17,7 @@ The OpenAPI definitions for this specification can be accessed [here](TBD).
 
 ### 2.2 Contract Negotiation Error
 
-In the event of a client request error, the connector must return an appropriate HTTP 4xxx client error code. If an error body is returned it must be
+In the event of a client request error, the connector must return an appropriate HTTP 4xx client error code. If an error body is returned it must be
 a [ContractNegotiationError](./message/contract-negotiation-error.json) with the following properties:
 
 | Field         | Type          | Description                                                 |
@@ -52,7 +52,7 @@ the [ContractNegotiation](./message/contract-negotiation.json):
 
 ```
 {
-  "@context":  "https://w3id.org/dspace/v0.8/context.json",
+  "@context": "https://w3id.org/dspace/v0.8/context.json",
   "@type": "dspace:ContractNegotiation"
   "@id": "urn:uuid:dcbf434c-eacf-4582-9a02-f8dd50120fd3",
   "dspace:state" :"REQUESTED"
@@ -76,12 +76,12 @@ POST https://connector.provider.com/negotiations/request
 Authorization: ...
 
 {
-  "@context":  "https://w3id.org/dspace/v0.8/context.json",
+  "@context": "https://w3id.org/dspace/v0.8/context.json",
   "@type": "dspace:ContractRequest"
   "@id": "urn:uuid:dcbf434c-eacf-4582-9a02-f8dd50120fd3",
   "dspace:dataSet": "urn:uuid:3dd1add8-4d2d-569e-d634-8394a8836a88",
   "dspace:offerId": "urn:uuid:2828282:3dd1add8-4d2d-569e-d634-8394a8836a88",
-  "dspace:callbackAddress": "https://......"
+  "dspace:callbackAddress": "https://..."
 }
 ```
 
@@ -100,7 +100,7 @@ the [ContractNegotiation](./message/contract-negotiation.json) message:
 Location: /negotiations/urn:uuid:dcbf434c-eacf-4582-9a02-f8dd50120fd3
 
 {
-  "@context":  "https://w3id.org/dspace/v0.8/context.json",
+  "@context": "https://w3id.org/dspace/v0.8/context.json",
   "@type": "dspace:ContractNegotiation"
   "@id": "urn:uuid:dcbf434c-eacf-4582-9a02-f8dd50120fd3",
   "dspace:state" :"REQUESTED"
@@ -121,7 +121,7 @@ POST https://connector.provider.com/negotiations/urn:uuid:dcbf434c-eacf-4582-9a0
 Authorization: ...
 
 {
-  "@context":  "https://w3id.org/dspace/v0.8/context.jsonn",
+  "@context": "https://w3id.org/dspace/v0.8/context.jsonn",
   "@type": "dspace:ContractRequestMessage",
   "dspace:processId": "urn:uuid:dcbf434c-eacf-4582-9a02-f8dd50120fd3",
   "dspace:offer": {
@@ -160,12 +160,12 @@ POST https://connector.provider.com/negotiations/urn:uuid:a343fcbf-99fc-4ce8-8e9
 Authorization: ...
 
 {
-  "@context":  "https://w3id.org/dspace/v0.8/context.json",
+  "@context": "https://w3id.org/dspace/v0.8/context.json",
   "@type": "dspace:ContractAgreementVerificationMessage",
   "dspace:processId": "urn:uuid:a343fcbf-99fc-4ce8-8e9b-148c97605aab",
   "dspace:consumerSignature": {
     "timestamp": 121212,
-    "hash": "....",
+    "hash": "...",
     "signature": ""
   }
 }
@@ -199,7 +199,7 @@ POST https://connector.consumer.com/callback/negotiations/urn:uuid:dcbf434c-eacf
 Authorization: ...
 
 {
-  "@context":  "https://w3id.org/dspace/v0.8/context.json",
+  "@context": "https://w3id.org/dspace/v0.8/context.json",
   "@type": "dspace:ContractOfferMessage",
   "dspace:processId": "urn:uuid:dcbf434c-eacf-4582-9a02-f8dd50120fd3",
   "dspace:offer": {
@@ -226,7 +226,7 @@ POST https://connector.consumer.com/negotiations/urn:uuid:a343fcbf-99fc-4ce8-8e9
 Authorization: ...
 
 {
-  "@context":  "https://w3id.org/dspace/v0.8/context.json",
+  "@context": "https://w3id.org/dspace/v0.8/context.json",
   "@type": "dspace:ContractAgreementMessage",
   "dspace:processId": "urn:uuid:a343fcbf-99fc-4ce8-8e9b-148c97605aab",
   "dspace:agreement": {
@@ -244,7 +244,12 @@ Authorization: ...
 #### 3.4.1 POST
 
 A provider can POST a [ContractNegotiationEventMessage](./message/contract-negotiation-event-message.json) to the `negotiations/:id/events` callback with an `eventType`
-of `finalized` to finalize a contract agreement. If the negotiation state is successfully transitioned, the consumer must return HTTP code 200 (OK). The response body is not
+of `FINALIZED` to finalize a contract agreement. If the negotiation state is successfully transitioned, the consumer must return HTTP code 200 (OK). The response body is not
 specified and clients are not required to process it. 
 
+### 3.5 The consumer `negotiations/:id/termination` resource
 
+#### 3.5.1 POST
+
+The provider connector can POST a [ContractNegotiationTerminationMessage](./message/contract-negotiation-termination-message.json) to terminate a negotiation. If the negotiation
+state is successfully transitioned, the consumer must return HTTP code 200 (OK). The response body is not specified and clients are not required to process it.