Quality Control Rewrite

[aGuyLearning]

Description of feature

I propose a rewrite of the quality control functions to work with single dispatch method rewrites described in #851 and #848.

To this end the qc_metrics function has to be looked at _obs_qc_metrics and _var_qc_metrics have to be rewritten using single dispatch to handle the different datatypes.

For now those will be dask.array and numpy.array

• single dispatch functions for _obs_qc_metrics
• single dispatch functions for _var_qc_metrics

This will most likely be handled in a big PR with the two issues mentioned.