CORE-5832 Refactored /public-app-groups endpoint.

Updated /apps/categories endpoint to accept a 'public' param so that only public categories can be returned.
Refactored kameleon.app-groups/get-visible-workspaces to accept a NULL workspace ID, and to fetch all results in one query.
Removed obsolete markdown documentation for /public-app-groups and /secured/app-groups.
CORE-5832 Refactor metadactyl.workspace.

Refactored the create-workspace-with-default-app-groups and create-default-workspace-subgroups functions for the new schema.
Fixed a bug in kameleon.app-groups/create-app-group
CORE-5832 Refactored /secured/get-analyses-in-group

Refactored the /secured/get-analyses-in-group/:app-group-id endpoint to /apps/categories/:category-id
Refactored some metadactyl.app-listings functions for the new schema.
Refactored metadactyl.app-listings/list-apps-in-virtual-group to work with UUIDs.
Refactored kameleon.app-listing/get-app-listing-base-query to work with Long limit and offset params, since compojure-api will automatically convert these params.
Removed obsolete markdown documentation for this endpoint.