Disallow project renaming

While this is possible in Atlas, the implementation in the operator
causes a new project to be created. Other resources like AtlasDeployment
then continue to track the clusters in the original project.

Since that behavior is clearly wrong, let's forbid changing this field
until AKO can implement renaming support for projects properly.

Author: tvdw-mongodb

api/v1/atlasproject_types.go

@@ -43,6 +43,7 @@ func init() {
 type AtlasProjectSpec struct {
 
 	// Name is the name of the Project that is created in Atlas by the Operator if it doesn't exist yet.
+	// +kubebuilder:validation:XValidation:rule="self == oldSelf",message="Name cannot be modified after project creation"
 	Name string `json:"name"`
 
 	// RegionUsageRestrictions designate the project's AWS region when using Atlas for Government.