r/blackbox-exporter: Rework to run as container

Instead of downloading the `blackbox_exporter` binary from GitHub and
copying it to the managed node, the _blackbox-exporter_ role now
installs _podman_ and configures a systemd container unit (Quadlet) to
run it in a container.  This simplifies the deployment considerably, and
will make updating easier (just run the playbook with `-e
blackbox_exporter_pull_image=true`).

roles/blackbox-exporter/tasks/install.yml

@@ -1,55 +1,4 @@
-- name: load installation variables
-  include_vars: install.yml
-  tags:
-  - always
-
-- name: load architecture variables
-  include_vars: '{{ item }}'
-  with_first_found:
-  - '{{ ansible_architecture }}.yml'
-  - arch-defaults.yml
-  tags:
-  - always
-
-- name: ensure blackbox_exporter release archive is available
-  delegate_to: localhost
-  become: false
-  get_url:
-    url: '{{ blackbox_xptr_tar_url }}'
-    checksum: 'sha256:{{ blackbox_xptr_cksm_url }}'
-    dest: '{{ playbook_dir }}/tmp/{{ blackbox_xptr_tar_name }}'
-  tags:
-  - download
-
-- name: ensure blackbox_exporter archive is unpacked locally
-  delegate_to: localhost
-  become: false
-  unarchive:
-    src: '{{ playbook_dir }}/tmp/{{ blackbox_xptr_tar_name }}'
-    dest: '{{ playbook_dir }}/tmp/'
-    remote_src: true
-    creates: '{{ blackbox_xptr_extract_dir }}/blackbox_exporter'
-  tags:
-  - unarchive
-
-- name: ensure blackbox_exporter is installed
-  copy:
-    src: '{{ blackbox_xptr_extract_dir }}/blackbox_exporter'
-    dest: /usr/local/sbin/blackbox_exporter
-    mode: u=rwx,go=rx
-  diff: false
-  notify:
-  - restart blackbox_exporter
-
-- name: ensure blackbox_exporter systemd unit is installed
-  file:
-    src: blackbox_exporter.service
-    dest: /etc/systemd/system/blackbox_exporter.services
-    mode: u=rw,go=r
-  notify:
-  - reload systemd
-  - restart blackbox_exporter
-  tags:
-  - service
-  - systemd
-
+- name: ensure podman is installed
+  package:
+    name: podman
+    state: present