Class that encapulates a UserOption. A UserOption is an option displayed to
the user. One or more of these UserOption's may be a part of an interaction.
EXAMPLES:
Interaction Example 1:
1. Continue with installation
2. Start Over
3. Exit
Here 1, 2 & 3 are display items and the rest of the Strings are localized
messages for each of those option. The localized message will be of the
format:
{0}. Continue with installation
Interaction Example 2:
[ ? : Help, < : Back, ]
Here ? and < are display items. The localized messages will looks like
{0} : Help
{0} : Back