Remove transient identifiers and partial success in response

As per the different discussions, this commit removes references to
identifiers used to identify parts of an inflight request that
disambiguate failure scenarios. They may be addressed later.

It also removes the partial successful reponse conveyed through a
redirect error code. The rationale to use only the 200 success code
is that the response for a batched request has been successfully
processed and the response may still contain references to items which
were not successful. Clients will have to introspect the response to
decide what to do with those failed items.

api/openapi.yaml

@@ -63,7 +63,7 @@ paths:
         - name: next_token
           in: query
           description: Indication of the offset to retrieve the next page on a previously initiated paginated request.
-          required: true
+          required: false
           schema:
             type: string
       responses:
@@ -95,12 +95,6 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/responses/CreateSessionsResponse'
-        '300':
-          description: Request modified or partially accepted
-          content:
-            application/json:
-              schema:
-                $ref: '#/components/responses/CreateSessionsResponse'
         '400':
           $ref: '#/components/responses/ErrorResponse'
         '403':
@@ -127,7 +121,7 @@ paths:
         - name: next_token
           in: query
           description: Indication of the offset to retrieve the next page on a previously initiated paginated request.
-          required: true
+          required: false
           schema:
             type: string
       responses:
@@ -158,12 +152,6 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/responses/DeleteSessionsResponse'
-        '300':
-          description: Request modified or partially accepted
-          content:
-            application/json:
-              schema:
-                $ref: '#/components/responses/DeleteSessionsResponse'
         '400':
           $ref: '#/components/responses/ErrorResponse'
         '403':
@@ -273,9 +261,6 @@ components:
           type: string
         location:
           $ref: '#/components/schemas/Location'
-        item_id:
-          type: string
-          description: unique identifier of the session in an aggregate
 
     SessionArray:
       title: BGP Sessions
@@ -310,9 +295,6 @@ components:
           description: |-
             unique identifier (also serves as request id)
             Could separate into local_ and peer_?
-        item_id:
-          type: string
-          description: unique identifier of the session in an aggregate
 
     SessionReferenceArray:
       title: BGP Session References