feat: add support for project_id in provider (#601)

Author: remyleone

docs/index.md

@@ -29,6 +29,7 @@ provider "scaleway" {
   access_key      = "<SCALEWAY-ACCESS-KEY>"
   secret_key      = "<SCALEWAY-SECRET-KEY>"
   organization_id = "<SCALEWAY-ORGANIZATION-ID>"
+  project_id      = "<SCALEWAY-PROJECT-ID>"
   zone            = "fr-par-1"
   region          = "fr-par"
 }
@@ -148,6 +149,9 @@ in this priority order.
 the `SCW_DEFAULT_ORGANIZATION_ID` [environment variable](https://github.com/scaleway/scaleway-sdk-go/blob/master/scw/README.md#environment-variables), or via a [shared configuration file](https://github.com/scaleway/scaleway-sdk-go/blob/master/scw/README.md#scaleway-config),
 in this priority order.
 
+- `project_id` - (Optional) The project ID that will be used as default value for all resources.
+  It can also be sourced from the `SCW_DEFAULT_PROJECT_ID` [environment variable](https://github.com/scaleway/scaleway-sdk-go/blob/master/scw/README.md#environment-variables), or via a [shared configuration file](https://github.com/scaleway/scaleway-sdk-go/blob/master/scw/README.md#scaleway-config), in this priority order.
+
 - `region` - (Optional) The [region](./guides/regions_and_zones.md#regions)  that will be used as default value for all resources. It can also be sourced from
 the `SCW_DEFAULT_REGION` [environment variable](https://github.com/scaleway/scaleway-sdk-go/blob/master/scw/README.md#environment-variables), or via a [shared configuration file](https://github.com/scaleway/scaleway-sdk-go/blob/master/scw/README.md#scaleway-config),
 in this priority order.

scaleway/provider.go

@@ -126,6 +126,21 @@ func Provider() func() *schema.Provider {
 					}),
 					ValidateFunc: validationUUID(),
 				},
+				"project_id": {
+					Type:        schema.TypeString,
+					Optional:    true, // To allow user to use organization instead of project
+					Description: "The Scaleway project ID.",
+					DefaultFunc: schema.SchemaDefaultFunc(func() (interface{}, error) {
+						if envProfile.DefaultProjectID != nil {
+							return *envProfile.DefaultProjectID, nil
+						}
+						if activeProfile != nil && activeProfile.DefaultProjectID != nil {
+							return *activeProfile.DefaultProjectID, nil
+						}
+						return nil, nil
+					}),
+					ValidateFunc: validationUUID(),
+				},
 				"region": {
 					Type:        schema.TypeString,
 					Optional:    true,