Support grouping options by category in help generators

[rvesse]

Requires adding a new category property to the @Option annotation (or a separate @OptionCategory) annotation to state category information

Help generators would then use this additional optional information to group options together in their outputs

[rvesse]

Suggested plan:

• Add category field to @Option annotation
• Add class level @OptionCategory annotation (and @OptionCategories) which has the following signature:
  @OptionCategory(title = "Title", description = "Describes the category", id = "id")
  Where id is the value that should be placed in the category field of @Option
• Discover and store @OptionCategory meta-data in CommandMetadata (and maybe GroupMetadata/GlobalMetadata as well?)
• Provide a Comparator<OptionMetadata> that does a category based sort of options
• Update help generator implementations to understand how to print options with their associated category descriptors