Add methods Help::optionListExcludingGroups to show only the specified options, including hidden ones

[remkop]

Currently, the Help::optionList methods are coarse-grained:

• they automatically filter the hidden options, with no easy way to customize this
• they show the options and any option groups

This makes it difficult to customize the options list.

This ticket proposes to add methods Help::optionListExcludingGroups that accept a list of options, and to show only the specified options, including hidden ones.