Add dstat supervisor job for Fetch

[sktometometo]

Add performance logging supervisor job for Fetch with dstat.

Some commits are excluded because of commit dependency

[sktometometo]

@k-okada

[sktometometo]

@708yamaguchi Could you explain what it is and why we need it?

[708yamaguchi]

I was monitoring fetch's computer resources to investigate a fetch freeze problem.