--output-prefix conflicts with --output-pattern (and is not really a prefix)

[Shnatsel]

--output-prefix flag currently defines not the prefix, but the entire filename (sans the extension). This flag conflicts with --output-pattern, so it is not possible to create filenames like custom_prefix-binary_name-target_platform.cdx.json which seems potentially useful - e.g. creating files starting with UUID and then being able to automatically discover all SBOMs generated by this run.

This is a behavior we have inherited, and it doesn't seem to make much sense. These two flags should be made compatible.