Clarify location header in "POST payments"

[ochatelain]

IS

• According to issue CON-1197 at SIX, the handling of the "header field" is different between the parties.
• Variants:
• Bank A: Absolut path
• Bank B: /payments/{submissionId}
• SIX-SIM: /payments/{submissionId}
• According to IETF: https://datatracker.ietf.org/doc/html/rfc7231#section-7.1.2 both is valid (absolute or relativ path)

SHOULD

• It would be easier for everyone, if we handle the topic in a uniform way
• Recommendation: /payments/{submissionId}
• Clarify the specification & add an example to the specification.