feat!: change label_selector from string to dict

[kimdre]

Breaking Change

This changes the label_selector variable type from string to dictionary to simplify managing the labels to search/filter for on rotation.

Example

Before:

label_selector: "created_by=ansible.hcloud-backup,host={{ inventory_hostname }}"

Now:

label_selector:
  created_by: ansible.hcloud-backup
  host: "{{ inventory_hostname }}"