👷(ci) sops: configure workflows to use sops secrets

Github secrets are difficult to maintain in time because we do not have
a way to track them efficiently. So to avoid this issue, we prefer to use
sops encrypted files to manage our secrets.

scripts/install-pre-commit-hook.sh

@@ -0,0 +1,29 @@
+#!/bin/bash
+
+PRE_COMMIT_FILE="$(dirname -- "${BASH_SOURCE[0]}")/../.git/hooks/pre-commit"
+
+cat <<'EOF' >$PRE_COMMIT_FILE
+#!/bin/bash
+
+# directories containing potential secrets
+DIRS="."
+
+bold=$(tput bold)
+normal=$(tput sgr0)
+
+# allow to read user input, assigns stdin to keyboard
+exec </dev/tty
+
+for d in $DIRS; do
+	# find files containing secrets that should be encrypted
+	for f in $(find "${d}" -type f -regex ".*enc.*"); do
+		if ! $(grep -q "unencrypted_suffix" $f); then
+			printf '\xF0\x9F\x92\xA5 '
+			echo "File $f has non encrypted secrets!"
+			exit 1
+		fi
+	done
+done
+EOF
+
+chmod +x $PRE_COMMIT_FILE