fix: disallow newer policies, users & groups with space characters (#14845)

space characters at the beginning or at the end can lead to
confusion under various UI elements in differentiating the
actual name of "policy, user or group" - to avoid this behavior
this PR onwards we shall reject such inputs for newer entries.

existing saved entries will behave as is and are going to be
operable until they are removed/renamed to something more
meaningful.

cmd/api-errors.go

@@ -383,6 +383,7 @@ const (
 	ErrAdminProfilerNotEnabled
 	ErrInvalidDecompressedSize
 	ErrAddUserInvalidArgument
+	ErrAdminResourceInvalidArgument
 	ErrAdminAccountNotEligible
 	ErrAccountNotEligible
 	ErrAdminServiceAccountNotFound
@@ -1825,6 +1826,11 @@ var errorCodes = errorCodeMap{
 		Description:    "User is not allowed to be same as admin access key",
 		HTTPStatusCode: http.StatusForbidden,
 	},
+	ErrAdminResourceInvalidArgument: {
+		Code:           "XMinioInvalidResource",
+		Description:    "Policy, user or group names are not allowed to begin or end with space characters",
+		HTTPStatusCode: http.StatusBadRequest,
+	},
 	ErrAdminAccountNotEligible: {
 		Code:           "XMinioInvalidIAMCredentials",
 		Description:    "The administrator key is not eligible for this operation",