update cnvkit/batch output channels

Is your feature request related to a problem? Please describe

Currently, cnvkit/batch outputs many different types of files to individual channels which may cause confusion. A few specific examples.

Two bed files are typically generated for each process. A target.bed and a antitarget.bed. Currently both are emitted to the bed channel.

A reference.cnn file will frequently (always?) be emitted with the other .cnn files which may include tumor and normal .cnn files. In tumor-normal mode you will generate: a reference.cnn, [tumor].antitargetcoverage.cnn, [tumor].targetcoverage.cnn, [normal].targetcoverage.cnn, [normal].antitargetcoverage.cnn.

Additionally, multiple .cns files will be emitted to the same channel [tumor].call.cns, [tumor].bintest.cns, [tumor].cns.

This pattern makes it difficult to use specific files downstream.

Describe the solution you'd like

Update the output channels to be more specific and have additional outputs for the different files generated.

Describe alternatives you've considered

No response

Additional context

No response

Start by locating the cnvkit/batch module and its nf-test coverage, then inspect how the target.bed, antitarget.bed, reference.cnn, other .cnn files, and .cns files are emitted. Define separate output channels for the distinct file types and update or add tests so each expected file is available downstream through the intended channel.