grch37: false can only be set once while grch37: true can be set per callset

[famosab]

The flag grch37 is used to define the reference genome used during variant calling in the config.

Expected behavior: Define the reference genome per callset and consequently use the correct rename-contigs contigs file (grch37_ucsc2ensembl or grch38_ucsc2ensembl).

Current behavior: For specific callsets grch37: true can be defined but setting grch37: false per callset does not work. The file for rename contigs has to be set manually.

[famosab]

Other issue with presets.yaml:

high_coverage: true works
high_coverage: false does not work, if its not set its set to false

[famosab]

Regarding grch37:

• Do we want to keep the possibility to evaluate on grch37 and also liftover from grch38 to grch37?
• Introducing auomatic rename chrs works easily (see PR fix: coverage and genome-build #113)