Fix: Same title subcategories get selected under other parent categories

This merge addresses the issue that is stated in #22 (closed), when entire category sections (eg. Core, Addons, Community, Kubernetes) are selected on the filter, any subcategories (eg. Monitoring, Security & Compliance, etc.) that are the same across other categories (parent categories such as Core, Addons, etc.) will then become selected as well. There are pictures in the issue to further demonstrate this bug.

The cncf landscape app by default is not setup to deal with subcategories that have the same name under other categories. If you look at the CNCF Landscape you will see that there are no duplicate named subcategories. As a workaround, I created code that will take the name of the parent category and append it to a subcategory's id (which is used in the filtering process) so that it is more unique. For example: security-compliance.core or monitoring.addons.