ci: move scripts into separate directory

So it's clean and tidy.

Signed-off-by: Petr Štetiar <ynezz@true.cz>
(cherry picked from commit 63ed733d30)

.github/workflows/formal.yml

@@ -27,7 +27,7 @@ jobs:
 
       - name: Test formalities
         run: |
-          source .github/workflows/ci_helpers.sh
+          source .github/workflows/scripts/ci_helpers.sh
 
           RET=0
           for commit in $(git rev-list HEAD ^origin/$BRANCH); do