Integrate Hangfire library to work for scheduler

[mmikirtumov]

Change our scheduler logic to work based on hangfire (https://www.hangfire.io/)

[Bounz]

Don't you want to use Horrarium instead of Hangfire? 😁

[vmayushan]

I think no, because there are many positive point to use Hangfire:

• largest community (in comparison with other schedulers)
• comprehensive documentation
• UI dashboard (easier to debug)
• proven over time

And the main point is to use widely spreaded instruments to flatten diffuculty for new developers :-)