Add configuration to show / hide the categories section in the sidebar

[dudil]

Yes

Yes

Yes

Yes

Add configuration to show / hide the categories section in the sidebar

Description

Added a configuration to show / hide the categories in the sidebar. Configuration also added (with true - show section) to the example Site

Motivation and Context

Not every blog would like to utilise the categories, an author should be able to control it with a configuration flag

Closes #99

How Has This Been Tested?

Tested on my own website with flag show / hide

Hugo Version: 0.34 Browser(s): Safari on Mac

Screenshots (if appropriate):

Types of changes

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

Checklist:

• [X] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation, including theme.toml, accordingly.
• [X] I have read the Contributing Document.