CI: Refactor log collection, collect also (COTS) UE logs

Refactor log handling in CI: collect according to currently used XML files. This makes it homogeneous in the pipelines, and avoids accidental overwriting (as happens in phytest-timing), as well as harmonizing the log placement (e.g., no YAML lookup in Ping/Iperf).

Allow to trace and archive UE logs (e.g., Quectel via QLog, Amarisoft UE logs). By default, no logs will be collected as of this MR, as many files are big.

Various cleanup in Jenkinsfiles, some bugfixes, add unit tests.