Create and validate install.sh signatures (#8312)

- SHA256 Signature of the install script
- Added a sha256sum invocations in the validate script.

  These calls will validate that the install script signatures
  match. And when the script is changed the signatures must be
  recalculated as reported by the error message in sha256sum.

Signed-off-by: Jose D. Gomez R <jose.gomez@suse.com>

scripts/validate

@@ -8,6 +8,9 @@ fi
 
 cd $(dirname $0)/..
 
+echo Running: install script signature checks
+sha256sum -c install.sh.sha256sum
+
 echo Running: go mod tidy
 go mod tidy