Add an exemption clause allowing potential code contributors to submit
issues if they state they would like to work on them, and note that
mobile-related pull requests are still accepted.
Suggested-by: Dean Herbert <pe@ppy.sh>
Due to an overwhelming amount of mobile reports that are not actively
being worked on (neither by the core team, due to more pressing
priorities, nor by external contributors) and take up considerable time
to manage, add an issue template that aims to enforce a temporary
moratorium on accepting mobile issues.