[Web][Restic][Dovecot][Dockerapi] Add restic backups with restore in the UI

- Scheduled, encrypted backups to S3, SFTP, REST or a local folder (new restic-mailcow container)
- Restore of mailboxes and whole domains in the UI, also deleted ones, for admins and domain admins
- Scope set by RESTIC_BACKUP_MODE in mailcow.conf (all, data, config)
- Optional backup before updates (update.sh), helper-scripts/restic.sh for a full restore

helper-scripts/dev_tests/run_python_unit_tests.sh

@@ -0,0 +1,23 @@
+#!/bin/bash
+# Runs the Python unit tests of the backup runners (tests/python/backup) in a throwaway container of the locally built
+# restic image: the backup runner (data/Dockerfiles/restic) and the dovecot restore runner (data/Dockerfiles/dovecot).
+# No network, no database: the tests replace the database and the clock.
+# Usage: helper-scripts/dev_tests/run_python_unit_tests.sh [unittest arguments, e.g. test_restic_runner]
+
+set -euo pipefail
+
+REPO_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
+IMAGE="mailcow-restic-tests"
+
+if [ $# -eq 0 ]; then
+  set -- discover -v
+fi
+
+docker build --quiet -t "${IMAGE}" "${REPO_DIR}/data/Dockerfiles/restic" > /dev/null
+
+docker run --rm --network none --security-opt label=disable \
+  -v "${REPO_DIR}/data/Dockerfiles/restic:/app/restic:ro" \
+  -v "${REPO_DIR}/data/Dockerfiles/dovecot:/app/dovecot:ro" \
+  -v "${REPO_DIR}/tests/python/backup:/tests:ro" \
+  -w /tests -e PYTHONPATH=/app/restic:/app/dovecot:/tests -e PYTHONDONTWRITEBYTECODE=1 \
+  --entrypoint python3 "${IMAGE}" -m unittest "$@"