Apart from icon hashes, add the ability to fileinfo to also present raw icon bytes

Since #339, `retdec-fileinfo` is able to present icon hashes. It could be also useful to add the ability to present raw icon bytes.

Notes:
- This output could be turned on via a new parameter. Alternatively, we could present the bytes every time (provided that the user requested `-v/--verbose` output). We can discuss this.
- I am not sure how useful would this piece of information be in the plain output format. I think it would be reasonable to only output the bytes when the output format is set to JSON.

Start at the retdec-fileinfo entry point and trace the existing icon-hash output added by #339. Decide whether raw bytes require a parameter or verbose mode, and whether they belong only in JSON; the work is done when the chosen behavior is documented and verified in the relevant output path.

Written by the indexing model from the issue text.