* The "old" Destination is now in destination-any but still called Destination.
* There is now a PublicDestination (w/o contactInfo and callback) and a PrivateDestination
* Removed notice about missing fields depending on scope (since its now obvious from the schema)

Reasoning: It't not version 20 but version 2.

Introduces multiple regions per service.

https://git.fitko.de/fit-connect/api/-/issues/86

this rename is done to have a more specific name for the field. just
having the generic word 'schema' might be confusing.

Fixes #83

The `externalDocs` element allows referencing an external
resource for extended documentation. Since we do it, lets
refer to it.

According to RFC 2616 (HTTP), the POST method is used to create a *new subordinate* of the resource identified by the Request-URI. In contrast, PUT is used to store the entity under the Request-URI.

Im Metadatenschema und in service-type.yml wird die URN einer Leistung im Attribut `identifier` hinterlegt. Dementsprechend sollte die Leistungs-URN auch in einem Zustellpunkt als `identifier` hinterlegt werden.

Die Beispiele zur Schema-URL sollten zur angegebenen Service-ID (Leika-ID) passen.

Zum konkreten Beispiel, siehe: https://fimportal.de/suche/%3FsearchWord=blaue;karte;eu%26L=1%26D=1%26P