Align `IokiSevice` passing in `ApiModels`

[StefMa]

Right know we have a mixed api design.
Sometimes we add the ApiModels to the function, sometimes we creaet the ApiModels there.

Example - creating the ApiModel:

kmp-passenger-api/library/src/commonMain/kotlin/com/ioki/passenger/api/IokiService.kt

Lines 677 to 689 in 84ae5d1

	override suspend fun createPaymentMethodFromStripePaymentMethod(
	stripePaymentMethodId: String,
	): ApiResult<ApiPaymentMethodResponse> = apiCall<ApiBody<ApiPaymentMethodResponse>, ApiPaymentMethodResponse> {
	val data = ApiPaymentMethodCreationRequest(
	"stripe",
	ApiPaymentMethodCreationRequest.Details(
	stripePaymentMethodId = stripePaymentMethodId,
	null,
	null,
	),
	)
	createPaymentMethod(body = ApiBody(data))
	}

Example - passing in the ApiModel:

kmp-passenger-api/library/src/commonMain/kotlin/com/ioki/passenger/api/IokiService.kt

Lines 554 to 557 in 84ae5d1

	override suspend fun createDevice(deviceRequest: ApiDeviceRequest): ApiResult<ApiDeviceResponse> =
	apiCall<ApiBody<ApiDeviceResponse>, ApiDeviceResponse> {
	createDevice(body = ApiBody(deviceRequest))
	}

We should align this and think about a common solution here.
Either passing in, or creating there.

[elmira-y]

We have decided to go with the first approach.
Only the relevant primitive flattened fields/enums would be exposed as input arguments.
The Request models must be internal, never public.