Latest news menu caption customization from template

[rica-carv]

Motivation and Context

Customization of latest news menu caption. As it is it will always render the default text.
Brought to V2.x standards

Description

Allows the use of $NEWS_MENU_TEMPLATE['latest']['caption'] = "TITLE"; at theme level, even enabling the use of shortcodes

How Has This Been Tested?

Tested with latest github e107 version

Types of Changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Performance enhancement (non-breaking change which improves efficiency)
• Code cleanup (non-breaking change which makes code smaller or more readable)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation (a change to man pages or other documentation)

Checklist

• My code adheres to the e107 code style standard.
• I have read the contributing document.
• I have added tests to cover my changes.
• All new and existing tests pass.