Jobs system

Description

Implement a job system that will allow to run code in background and provide feedback to the user, instead of just running things in goroutines without proper control.

This change will require a new database table to store the job status along with UI elements to display current running jobs, list of past jobs, etc.

Investigate libraries that can help with this or do a basic implementation ourselves.

Configuration should be added to set how many background jobs does the user allow, maxing out by default to the number of CPUs.