Implement proper task management / plugin scheduling

[shard77]

Currently, the scheduler / worker implementation is very basic, just what we need to test out plugins.

We should do a state-of-the-art check and see what solutions could be the best-fitting ones.
Note that we want something that is scalable, but it shouldn't hinder personal usage.

Open to suggestions!

[shard77]

#40 has been merged which includes a lot of upgrades to the task scheduler implementation. Leaving this issue open in case I do have some other ideas which would enhance the scheduler even more. Moving this issue to the backlog for now.