There is a wrong directory path to all.yml and vsphere.yml. The wrong directory is `inventory/sample/group_vars/all.yml` and `inventory/sample/group_vars/all/vsphere.yml` which should be `inventory/sample/group_vars/all/all.yml` and `inventory/sample/group_vars/all/vsphere.yml`.
* Fix invalid link to Ansible documentation
* Fix invalid link to mitogen doc page
* Fix invalid link to calico doc page
* Fix all invalid links to doc pages