Fixes #21119 - set taxonomies in API

With this we correctly set the default taxonomy for non-admin users
in API calls. Admins are not touched at all, their context remains
"any context" for API calls. This also refactors various places
where tried to set the right taxonomy and combines them into single
one. This makes API requests work for org admins with single org.
As long as they don't specify any --organization-id(s) or
--location-id(s) parameters, the resource can be created in users'
default organization and location. This is as consistent with UI
as possible and rely on the same bug present in Taxonomix
in combination with DirtyAssociations.