Output filenames should be configurable

[JonZeolla]

Describe the issue
Currently the output filenames are a part of a hard-coded mapping. They should be configurable.

In some cases users can redirect stdout/stderr to meet their needs, but this is not the case in my situation.

[JonZeolla]

It looks like parser args are here which gets parsed into config. Looks like this was recently touched via 11edf57

[gruebel]

yeap, you can leverage my change like described in the help text

checkov -d . -o cli -o junitxml --output-file-path console,results.xml

for a single output you need still to append a comma, otherwise it will use the old mechanism.

[JonZeolla]

That works, thanks! By the way, I did read that help text but didn't expect it would work that way.