Docs links: add Communicating, User Guide, Forum

[himdel]

Issue: https://forum.ansible.com/t/issues-creating-an-account/2197/4

Adds the following links to the documentation menu:

• Ansible Community Forum - https://forum.ansible.com
• Communicating with the Ansible community - https://docs.ansible.com/ansible/latest/community/communication.html
• Community User Guide - https://ansible.readthedocs.io/projects/galaxy-ng/en/latest/community/userguide/

(along with the existing training & customer support)