Introduce `bench log` to deal with all-things-log

[surajshetty3416]

We should have bench log commands to pull and display logs available in bench.

• It should show last n line of specific type of commands

bench log --source worker -n 100
bench log --source scheduler -n 100
bench log --source web.error -n 100

• It should also show logs related to specific sites

bench --site sitename log --source web -n 100

• It should have the ability to stream (or tail) log files

bench --site sitename log --source web -n 100 --stream

• It can have filters (grep, from, to, etc.)

bench --site sitename log --source web.error -n 100 --stream --find "ValidationError:"
bench --site sitename log --source web --from "2022-02-02" --to "2022-05-02"