feat: initial refactor and feature implementation

This is the first major commit after forking the original project. The
script has been almost completely rewritten to add new features.

- Implement AES-256 encryption with configurable PBKDF2 iterations (default 600k).
- Add Telegram integration for status updates and optional file uploads.
- Rework backup logic to use safe `sqlite3 .backup` method.
- Add GitHub Action to build/publish multi-arch Docker images and create
  GitHub Releases on git tags.

BREAKING CHANGE: The project is not backward-compatible, configuration
and behavior are entirely different from the original version.

.github/workflows/dockerize.yml

@@ -1,42 +1,68 @@
 name: Dockerize
 
-# When to run.
-# In this case, manual only.
 on:
-  workflow_dispatch:
+  push:
+    tags:
+      - "v*"
 
-# Instructions on what to do.
-# In this case, 'build' is the job and Ubuntu is the OS to run the job on.
 jobs:
-  main:
+  release-and-publish:
     runs-on: ubuntu-latest
-    env:
-      USERNAME: jmqm
-      REPOSITORY: vaultwarden_backup
-      TAG: latest
+
+    permissions:
+      contents: write
+      packages: write
 
     steps:
-      - name: Check out repo
-        uses: actions/checkout@v2.3.4
+      # Step 1: Check out the repository code
+      - name: Check out repository
+        uses: actions/checkout@v4
 
-      - name: Log in to Docker Hub
-        uses: docker/login-action@v1.10.0
-        with:
-          username: ${{ env.USERNAME }}
-          password: ${{ secrets.DOCKER_HUB_PASSWORD }}
-      
-      - name: Update README and description
-        uses: peter-evans/dockerhub-description@v2.4.3
-        with:
-          username: ${{ env.USERNAME }}
-          password: ${{ secrets.DOCKER_HUB_PASSWORD }} # This action does not support tokens.
-          repository: ${{ env.USERNAME }}/${{ env.REPOSITORY }}
-          short-description: ${{ github.event.repository.description }}
-          readme-filepath: ./README.md
+      # Step 2: Set up QEMU for multi-architecture builds (e.g., for arm64)
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
 
-      - name: Build image and push to Docker hub
-        uses: docker/build-push-action@v2.6.1
+      # Step 3: Set up Docker Buildx, which is required for multi-platform builds
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      # Step 4: Log in to the GitHub Container Registry
+      - name: Log in to GitHub Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      # Step 5: Extract metadata for Docker tags and labels
+      - name: Extract Docker metadata
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ghcr.io/${{ github.repository }}
+          tags: |
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=semver,pattern={{major}}
+          flavor: |
+            latest=auto
+
+      # Step 6: Build and push the multi-platform Docker image
+      - name: Build and push Docker image
+        id: build-and-push
+        uses: docker/build-push-action@v6
         with:
           context: .
+          platforms: linux/amd64,linux/arm64
           push: true
-          tags: ${{ env.USERNAME }}/${{ env.REPOSITORY }}:${{ env.TAG }}
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+
+      # Step 7: Create a GitHub Release
+      - name: Create GitHub Release
+        uses: ncipollo/release-action@v1
+        with:
+          generateReleaseNotes: true
+          token: ${{ secrets.GITHUB_TOKEN }}