Add a custom callback plugin for managing logs

To be tested in our collection.

Changes to ansible.cfg:

[defaults]
stdout_callback = filtering_syslog
callback_plugins = ./callback_plugins << Not sure.

How to use it in plays: By default you have no output, if you need the task to be printed add tag [print_action]. Example:

---
- name: A verbose playbook
  hosts: localhost
  connection: local
  gather_facts: false
  tasks:
    - name: Print something on screen
      debug:
        msg: "First something"

    - name: Print something on screen again
      debug:
        msg: "Second something"

    - name: Print something on screen and again
      debug:
        msg:
          "Third something very long
          with multiline
          in it
          "
      tags: [print_action]

    - name: Print something on screen again again
      debug:
        msg: "5th something"