Add timed tasks

[BlaCoiso]

This would allow commands/modules to schedule tasks to be executed in a specific context at a specific time, with some task data.
These would be triggered with a timedTask event, with arguments name, context and data.
name would be name of the task, context is the context of the task (user and/or guild), data would be any data required for that task.
The event would only be triggered to the module that registered the task.