Change builder package fetch query

[Vel1khan]

Currently, if any build for a specific package is already present in the builds db, it is not fetched anymore. Since we are now building each package multiple times, if the experiment is stopped halfway or crashes, any builds left for the package are not resumed.

How to fix:

1. Fetch ALL packages from tags table matching our requirements
2. Let all build parameters be determined, but right before building check whether a build with those exact parameters already exists. If yes, skip this build.