CreateImageWizard: warning for unavailable on-prem OpenSCAP

Add a warning if the required packages for the OpenSCAP step are not available.

src/Utilities/useOnPremOpenSCAP.tsx

@@ -0,0 +1,36 @@
+import { useEffect, useState } from 'react';
+
+import cockpit from 'cockpit';
+
+export const useOnPremOpenSCAPAvailable = () => {
+  const [packagesAvailable, setPackagesAvailable] = useState(false);
+
+  useEffect(() => {
+    const checkPackages = async () => {
+      try {
+        const openSCAPAvailable = await cockpit.spawn(
+          ['rpm', '-qa', 'openscap-scanner'],
+          {}
+        );
+
+        const ssgAvailable = await cockpit.spawn(
+          ['rpm', '-qa', 'scap-security-guide'],
+          {}
+        );
+
+        setPackagesAvailable(openSCAPAvailable !== '' && ssgAvailable !== '');
+      } catch {
+        // this doesn't change the value,
+        // but we need to handle the error
+        // so just set the value to false
+        setPackagesAvailable(false);
+      }
+    };
+
+    if (process.env.IS_ON_PREMISE) {
+      checkPackages();
+    }
+  }, []);
+
+  return packagesAvailable;
+};