FEATURE: Add more paragraphs to category description, add inline 'Read more' link

[NateDhaliwal]

This PR adds 2 new features:

1. More paragraphs to the category description. This adds a new setting, show_full_category_description (default false) to show the full post contents of the About category topic.
2. Inline 'Read more' link. This adds a new setting inline_read_more (default false) to append the 'Read more' link at the end of the category description, instead of a few lines down.

Things to note:

• The inline 'Read more' link is not added to the end of the category description when show_full_category_description is true
• There is no override regarding the category descriptions: you can set both show_category_description and show_full_category_description to true, and both descriptions will be shown. This may be addressed in a later PR.