[IMP] reorganize project directory structure

Restructure the project for better organization and maintainability:

New structure:
  ./upgrade.sh              - Main entry point (unchanged)
  ./lib/common.sh           - Shared bash functions
  ./lib/python/             - Python utility scripts
  ./scripts/                - Workflow scripts (prepare_db, finalize_db)
  ./config/                 - Configuration files (compose.yml)
  ./versions/{13..18}.0/    - Version-specific migration scripts

File renames:
  - pre_migration_view_checking.py -> lib/python/check_views.py
  - post_migration_fix_duplicated_views.py -> lib/python/fix_duplicated_views.py
  - post_migration_cleanup_obsolete_modules.py -> lib/python/cleanup_modules.py

Benefits:
  - Single entry point visible at root level
  - Clear separation between shared code, scripts, and config
  - Shorter, cleaner Python script names (context given by caller)
  - Easier navigation and maintenance

scripts/prepare_db.sh

@@ -0,0 +1,73 @@
+#!/bin/bash
+set -euo pipefail
+
+ODOO_SERVICE="$1"
+DB_NAME="$2"
+DB_FINALE_MODEL="$3"
+DB_FINALE_SERVICE="$4"
+
+TMPDIR=$(mktemp -d)
+trap 'rm -rf "$TMPDIR"' EXIT
+
+echo "Start database preparation"
+
+# Check POSTGRES container is running
+if ! docker ps | grep -q "$POSTGRES_SERVICE_NAME"; then
+    printf "Docker container %s is not running.\n" "$POSTGRES_SERVICE_NAME" >&2
+    exit 1
+fi
+
+EXT_EXISTS=$(query_postgres_container "SELECT 1 FROM pg_extension WHERE extname = 'dblink'" "$DB_NAME") || exit 1
+if [[ "$EXT_EXISTS" != "1" ]]; then
+    query_postgres_container "CREATE EXTENSION dblink;" "$DB_NAME" || exit 1
+fi
+
+# Neutralize the database
+SQL_NEUTRALIZE=$(cat <<'EOF'
+/* Archive all the mail servers */
+UPDATE fetchmail_server SET active = false;
+UPDATE ir_mail_server SET active = false;
+
+/* Archive all the cron */
+ALTER TABLE ir_cron ADD COLUMN IF NOT EXISTS active_bkp BOOLEAN;
+UPDATE ir_cron SET active_bkp = active;
+UPDATE ir_cron SET active = False;
+EOF
+	      )
+echo "Neutralize base..."
+query_postgres_container "$SQL_NEUTRALIZE" "$DB_NAME" || exit 1
+echo "Base neutralized..."
+
+#######################################
+## List add-ons not in final version ##
+#######################################
+
+SQL_MISSING_ADDONS=$(cat <<EOF
+SELECT module_origin.name
+FROM ir_module_module module_origin
+LEFT JOIN (
+    SELECT *
+    FROM dblink('dbname=${FINALE_DB_NAME}','SELECT name, shortdesc, author FROM ir_module_module')
+    AS tb2(name text, shortdesc text, author text)
+) AS module_dest ON module_dest.name = module_origin.name
+WHERE (module_dest.name IS NULL)
+  AND (module_origin.state = 'installed')
+  AND (module_origin.author NOT IN ('Odoo S.A.', 'Lokavaluto', 'Elabore'))
+ORDER BY module_origin.name;
+EOF
+)
+echo "Retrieve missing addons..."
+missing_addons=$(query_postgres_container "$SQL_MISSING_ADDONS" "$DB_NAME")
+
+log_step "ADD-ONS CHECK"
+echo "Installed add-ons not available in final Odoo version:"
+echo "$missing_addons"
+confirm_or_exit "Do you accept to migrate with these add-ons still installed?"
+
+PYTHON_SCRIPT=pre_migration_view_checking.py
+echo "Check views with script $PYTHON_SCRIPT ..."
+exec_python_script_in_odoo_shell "$DB_NAME" "$DB_NAME" "$PYTHON_SCRIPT"
+
+confirm_or_exit "Do you accept to migrate with the current views state?"
+
+echo "Database successfully prepared!"