USB mouse suspends on AC powered system

[nightflier]

7.2 STD both versions, couple years old i5 HP desktop:

USB mouse goes to sleep after one second. Clicks wake it up after about a half second.

We should have a way of controlling this behaviour for those who prefer different settings.

[nightflier]

This fixed it for my machine:

laptop-mode-tools: https://github.com/rickysarraf/laptop-mode-tools

[nightflier]

laptop-mode-tools now in repo, and works.