telegraf: drop agent configuration stuff

Servers will be switched to Prometheus. Telegraf remains as a SNMP proxy
(see following commit).

roles/telegraf/tasks/main.yml

@@ -1,11 +1,22 @@
-- name: Get influxdb info
-  set_fact:
-    influxdb_info: '{{ lookup("passwordstore", "vm/"~influxdb_host, returnall=true, missing="empty") | from_yaml }}'
-
-- name: Create influxdb token for this host
-  include_tasks: token.yml
-  when: 'not ansible_check_mode and "influxdb_token" not in password'
-
-- name: Install telegraf on Debian
-  include_tasks: debian.yml
+- name: Add telegraf package repo on Debian
   when: ansible_os_family == "Debian"
+  deb822_repository:
+    name: influxdata
+    uris: https://repos.influxdata.com/debian
+    suites: stable
+    components: main
+    architectures: amd64
+    signed_by: https://repos.influxdata.com/influxdata-archive.key
+  notify: update package cache
+
+- meta: flush_handlers
+
+- name: Install telegraf
+  package:
+    name: telegraf
+
+- name: Enable telegraf service
+  service:
+    name: telegraf
+    enabled: true
+    state: started