Make laptop role optional

[petRUShka]

Sometimes it is useful to install spark on desktop. In that case, tlp and friends are useless.

My proposal is to add laptop variable and don't apply laptop role if variable is False.

Something like:

  - { role: laptop, tags: ['laptop'], when: "laptop | bool" }

[pigmonkey]

Similar to #124, the idea is that you'd clone the repo, create your own branch, and remove whatever roles you don't want from the playbook. I don't think there is any additional value in creating a variable for the role.

If Ansible can reliably detect if a machine is a laptop or not, and stores that in one of its default system vars, I'd be good with adding that as a condition to the role. Similar to how Ansible can detect if it is running on a Thinkpad or not, and how we use that to decide if we should run that role. I haven't looked to see if there is some sort of generic "laptop" variable.

[petRUShka]

The only idea I have is to check whether the device has battery. Something like this:

shell: '[ -d /sys/class/power_supply/BAT0 ] && echo "Battery found" || echo "No battery"'