Sets up backups to Cloudflare R2

# Instalation

In requirements.yml:

```
roles:
  - src: git+https://git.internet-czas-dzialac.pl/kuba/ansible-setup-backups.git
    version: master
    name: setup-backups
```

# Setup

Create a Cloudflare R2 account and create an admin token.

Create a file under `templates/backup-scripts/<hostname>.sh.j2` that
is a shell script that prepares the data for backup - leave empty if
not necessary.

Then in your playbook run:

```yml

- name: "Setup backups"
  hosts: ansible1
  roles:
    - setup-backups
  vars:
    backup_bucket_prefix: "backup"
    all_backup_paths:
      - /var/homebox/data
    cloudflare_r2_access_key: "cloudflare R2 Access key (for S3-type API)"
    cloudflare_r2_secret_key: "cloudflare R2 secret key (for S3-type API)"
    cloudflare_r2_endpoint: https://some_endpoint.r2.cloudflarestorage.com
    BACKUP_PASSWORD: password
```