Remove deprecated flagger code
The flagger code is now integrated in DP3, see the documentation and/or the code. This is reimplementation of the original code using XTensor. Moreover, it has a number of unit tests to illustrate that it can detect outlier antennas and stations in data. The flagger code in aartfaac-tools on the other hand, was only shown to reproduce the results from the original scripts and is therefore tested less well.
The flagging code should either be removed from aartfaac-tools completely, or it should be updated to match the code in DP3.