feat: Add Lexicographical Types to condition/strings

[jshlbrd]

Description

• Adds a greater_than type to condition/strings
• Adds a less_than type to condition/strings

Motivation and Context

Lexicographical string comparison can be useful when retroactively parsing data (e.g., during rehydration) or for validating data. These new types use the same syntax as conditions/length.

How Has This Been Tested?

Added new unit tests.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.