Improve get workflow resource usage

Current situation

get workflow gets all workflow event before processing.

Desired outcome

A progressive handling would be nicer (faster response time, less memory usage).

Analysis

run workflow --wait and get workflow were keeping the whole set of workflow events in memory, which can be very large.

The change process them one by one, so at most a page is kept in memory.

This was done for all output formats (including json and yaml).