Add progress logging (monitor mode) for scraping #770

❗ Note: This is a starting point for discussion, not a final decision. The team should review and adjust before any implementation begins.❗

A feedback from @honzajavorek:

I do think that Crawlee should log some "progress" information about requests made or - especially - items scraped. It's so weird to run the program and then just look at the program as if it hanged, waiting if something happens or not. E.g. Scrapy logs how many items per minute I scraped, which I personally find super useful.