cli: print JSON list continuously, not at once when all items are fetched
For performance reasons we cannot simply add everything to a list and then
use `json_dumps` function to print all JSON at once. For large projects this
would mean (tens) of minutes of no output, which is not user-friendly.
Instead, let's utilize `json_dumps` to convert each object to a JSON
string and print it immediately. By doing so, we need to manually take
care of opening and closing list brackets and separators.
Within this commit, I also did some unrelated changes that were
necessary because the code is too tied together.
We didn't print a valid JSON output for large projects that required
paginating over more than just one page. The problem was repeatedly
opening and closing the main list. This commit fixes it.
I simplified the `JsonPrinter` as much as possible since 1) it was really
hard to understand, and 2) there was a _leak_ causing iteration over
the whole `self.output_info` over and over again each time a new item
was added, resulting in the printer being increasingly slower.
I also updated the printer usage for listing builds. It doesn't make
sense to create a new printer for each page of builds. Instead, we
should simply create a printer, use it for the whole loop and finish