DSL2 Metagenomics - Update the test-datasets and input-files for test profiles

[merszym]

Problem

We currently use the test-profiles for the metagenomics profilers just as a technical test, that the pipeline runs smootly. But the output is always empty, because the current test-input data (mammoth) and test-databases for the metagenomics profiler tools (bacterial) dont match.

Approach

We should either provide a test-file that has some bacterial reads retained after host-removal or update the test-databases to have some "real" tables produced as output after the end of the respective test-runs.

[merszym]

Waiting for now to incorporate the tests in the new nf-test framework

[merszym]

Classifier	Input-Fasta	Database	TODO?
Krakenuniq	Mammoth	Mammoth	DONE
Kraken2	Mammoth	contains Mammoth	Nothing
Metaphlan	Mammoth	To check	To check
Malt	Mammoth	contains Mammoth	Nothing