Implement the logic to create the CAPIF event subscription (POST)

go-apps/meep-app-enablement/api/capif-mgmt/swagger.yaml

go-apps/meep-app-enablement/server/capif-mgmt/convert.go

...eep-app-enablement/server/capif-mgmt/model_capif_event.go

...-enablement/server/capif-mgmt/model_capif_event_filter.go

...-enablement/server/capif-mgmt/model_event_subscription.go

...l_service_availability_notification_service_references.go

...pps/meep-app-enablement/server/capif-mgmt/service-mgmt.go