Update package integration docs

Review package integration docs and add steps for Big Bang MR/all packages pipeline

changed milestone to %2.20.0

added kindmaintenance priority4 labels

set weight to 1

changed iteration to Big Bang Iterations Jan 23, 2024 - Feb 5, 2024

assigned to @chris.oconnell

mentioned in merge request !3767 (merged)

closed with commit 15cf806e

mentioned in commit 15cf806e