Generate EE-specific JavaScript fixtures into ee/ directory
This is a follow-up of https://gitlab.com/gitlab-org/gitlab-ee/issues/10386 and a requirement for https://gitlab.com/gitlab-org/gitlab-ce/issues/49127.
Currently fixtures in ee/spec/javascripts/fixtures/
output to spec/javascripts/fixtures/
. We need to change that to ee/spec/javascripts/fixtures/
. This requires updating the Rake task (karma:fixtures
) and also Karma and Jest configuration.