Update springboot version of the Policy Management Service (version 2.5)

Update springboot version of the Policy Management Service (version 2.5)

This required some changes due to not backwards compatible changes.
 - The API to springboot WebClient is changed, which is wrapped in class AsyncRestClient.
 - The validation of trusted certs is made more strict. The Owner field of the peer cert must contain the name ofthe using host.
   The uniitest tests this, so the cert in config is updated (Owner is "localhost").

Change-Id: Ia954b0ee5942884cd4b9fd82769bc8089dc35c53
Issue-ID: CCSDK-3421
Signed-off-by: PatrikBuhr <patrik.buhr@est.tech>