Restore methods with optional params for 4.19 compatability

[vishesh92]

Add optional params from #77 to the requiredParams.go.

[shwstppr]

Code LGTM

[weizhouapache]

@vishesh92
clustertype is always an optional parameter, right?
In the official ACS/cloudstack-go releases I mean.

[weizhouapache]

I checked the diff betwen this PR and latest v2.15.0

1. guest OS (no need to fix I think)

 type GuestOSServiceIface interface {
        AddGuestOs(p *AddGuestOsParams) (*AddGuestOsResponse, error)
-       NewAddGuestOsParams(details map[string]string, oscategoryid string, osdisplayname string) *AddGuestOsParams
+       NewAddGuestOsParams(oscategoryid string, osdisplayname string) *AddGuestOsParams
        AddGuestOsMapping(p *AddGuestOsMappingParams) (*AddGuestOsMappingResponse, error)

...
-       NewUpdateGuestOsParams(details map[string]string, id string, osdisplayname string) *UpdateGuestOsParams
+       NewUpdateGuestOsParams(id string, osdisplayname string) *UpdateGuestOsParams

2. CKS

diff --git a/cloudstack/KubernetesService.go b/cloudstack/KubernetesService.go
index 07bcd3e..4dcf1f1 100644
--- a/cloudstack/KubernetesService.go
+++ b/cloudstack/KubernetesService.go
@@ -31,7 +31,7 @@ type KubernetesServiceIface interface {
        AddKubernetesSupportedVersion(p *AddKubernetesSupportedVersionParams) (*AddKubernetesSupportedVersionResponse, error)
        NewAddKubernetesSupportedVersionParams(mincpunumber int, minmemory int, semanticversion string) *AddKubernetesSupportedVersionParams
        CreateKubernetesCluster(p *CreateKubernetesClusterParams) (*CreateKubernetesClusterResponse, error)
-       NewCreateKubernetesClusterParams(description string, kubernetesversionid string, name string, serviceofferingid string, size int64, zoneid string) *CreateKubernetesClusterParams
+       NewCreateKubernetesClusterParams(clustertype string, name string, zoneid string) *CreateKubernetesClusterParams
        DeleteKubernetesCluster(p *DeleteKubernetesClusterParams) (*DeleteKubernetesClusterResponse, error)
        NewDeleteKubernetesClusterParams(id string) *DeleteKubernetesClusterParams
        DeleteKubernetesSupportedVersion(p *DeleteKubernetesSupportedVersionParams) (*DeleteKubernetesSupportedVersionResponse, error)

[weizhouapache]

thanks @vishesh92

it looks terraform will not work

https://github.com/apache/cloudstack-terraform-provider/blob/d524e07e497b44caf3252fe9ffeefbc6bd138570/cloudstack/resource_cloudstack_kubernetes_cluster.go#L165

	// Create a new parameter struct
	p := cs.Kubernetes.NewCreateKubernetesClusterParams(name, kubernetesVersionID, name, serviceOfferingID, size, zoneID)

[weizhouapache]

checked the diff between v2.15.0 and this PR, did not find other compatibility issues except the guest OS

I think it is good to merge. @vishesh92 thanks