Defining tumor purity/ploidy

[mbenary]

Is your feature request related to a problem? Please describe.
Tumor purity is important to have context for variant allele frequencies. The available wrapper for ascat is not in a stable state and output is not available for cbioportal-export.

Describe the solution you'd like
First, the wrapper for ascat needs to be tested. Second, the output needs to be available for cbioportal-export and that should be homogenous across different tools.

Describe alternatives you've considered
Other options for tools would be Theta2 or PureCN. Maybe a comparison of tools to understand robustness is necessary.

Additional context
None.