Support multiple bed files for targeted sequencing analysis

[bounlu]

Description of feature

For the targeted sequencing analysis, I have multiple target regions for different features and I want to check metrics for them separately. I want to provide multiple bed files with --target_regions_file and I would like to see a separate section in MultiQC for each of them.

something like this:
--target_regions_file regions1.bed --target_regions_file regions2.bed --target_regions_file regions3.bed

or even better like this:
--target_regions_file regions1.bed,regions2.bed,regions3.bed