CORE-5832 Refactored /apps/:id/copy-pipeline

Implemented logic to copy a pipeline and its steps and mappings in metadactyl.
Updated the endpoint so that the email query param is now required.
Added a metadactyl.workspace/get-workspace function that does not attempt to create the user's workspace, and throws an error if one does not exist.
CORE-5832 Fix for /secured/bootstrap endpoint.

Refactored get-or-create-workspace logic from metadactyl.workspace into donkey.persistence.workspaces, so that the appropriate workspace categories can be created in Donkey by the bootstrap endpoint.
Removed obsolete get-or-create-workspace-for-user and get-or-create-user functions from kameleon.queries.
Refactored metadactyl.app-categorization and metadactyl.app-listings to use the metadactyl.workspace/get-workspace function.
Added default workspace category names to donkey configs.