This is part of the work to implement the display of Dependency Scanning
results in the Dependency List[1].

The bulk of this is simply moving the existing Vuex store to a reusable
module. The purpose of this is to facilitate adding a second instance of
the module, so that there can be two independent dependency lists at
once, as specified in the [feature's issue][1].

[1]: https://gitlab.com/gitlab-org/gitlab-ee/issues/10077