Move GitlabSubscriptionHistory to GitlabSubscriptions::SubscriptionHistory

Closes #355985

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/159901



Merged-by: Adam Hegyi <ahegyi@gitlab.com>
Approved-by: Josianne Hyson <jhyson@gitlab.com>
Approved-by: Pam Artiaga <partiaga@gitlab.com>
Approved-by: Brian Williams <bwilliams@gitlab.com>
Approved-by: Adam Hegyi <ahegyi@gitlab.com>
Reviewed-by: Josianne Hyson <jhyson@gitlab.com>
Reviewed-by: Sheldon Led <sheldonled@gitlab.com>
Reviewed-by: Pam Artiaga <partiaga@gitlab.com>
Co-authored-by: Sheldon Led <sheldonled@gitlab.com>