What are match-key permissions and why would I use them?

Question	What are match-key permissions and why would I use them?
Answer	Match-key permissions provide a more granular level of access control beyond the standard zone, page, and category permissions. They allow you to restrict access based on specific "match-keys", which are unique identifiers for different actions or content within Composr. For instance, you could use match-key permissions to prevent guests from submitting banners or to restrict access to the member directory for all but specific usergroups. You can also specify custom access denied errors for each match-key. A "match-key" is typically a page-link, such as `cms:cms_banners:add`.