Properly implement `RequestList`

[janbuchar]

The current implementation is very basic and mostly serves for testing. We should make it more like https://github.com/apify/crawlee/blob/master/packages/core/src/storages/request_list.ts

it should

• support loading remote request lists in the background
• have persistent state

[vdusek]

Closing, as this was addressed in #777.

[janbuchar]

I beg to differ, it still doesn't have persistence