Show job progress correctly

[msm-code]

Feature Category

• Correctness
• User Interface / User Experience
• Performance
• Other (please explain)

Describe the problem

See #178 for my previous attempt at this problem.

There is no way to tell how many files from ursdabb will match the query before actually running it, and it can take between few seconds to many minutes (especially for queries for many files at once).
When the ursadb query is very precise (for example, returns only a few files and all of them match the yara rule) this leads to weird situations where the query is "100% done" all the time, but still in processing.

Describe the solution you'd like

I'll update this issue with my UI mockup proposotion soon

Describe alternatives you've considered

#178