Feature: Multiple Options

[hammer065]

This pull request adds the possibility to specify multiple user_id arguments and multiple --path options in the :delete_old and :generate-all commands respectively.

It does this by adding the respective Symfony ::IS_ARRAY mode specifiers to the arguments/options, adapting the if checks if needed and wrapping the existing code paths inside a foreach loop.

[st3iny]

Looks good. Thank you for the contribution :)

One minor thing though: Please squash the typo commits. I'm ok with having three commits (one for each command/parameter). However, those fixups should be squashed with their respective feature commit.