Until now the loader tests did not detect if a file in testdata existed,
but was missing from the actual results. This patch fixes the problem.
It also removes various files that are not needed.
The testdata folder now represents which files end up in a cluster 1:1.
The constellationUID is sometimes interpreted as integer if it contains
0e, as the yaml parsing interprets that as scientific notation.
Since it is a best practices to quote string fields anyways this patch
also quotes other fields where an actual string is required.
