Changes to Create marketplace

added the optional property message to the response with the 400 status

the endpoint scheme security bearerAuth was added to the API

the endpoint scheme security denApiKey was added to the API

added the required property item/externalKey to the response with the 201 status

added the optional property capability to the response with the 400 status

the item/createdByOrgMembershipId response's property pattern ^om_.* was removed for the status 201

the item/id response's property pattern ^mkt_.* was removed for the status 201

the item/organizationId response's property pattern ^org_.* was removed for the status 201