Subscription / Billing bug fixes and some enhancements

[Monilprajapati]

shaffuru PR : https://github.com/Shuffle/shaffuru/pull/808

[0x0elliot]

go run *.go
# github.com/shuffle/shuffle-shared
/Users/aditya/go/pkg/mod/github.com/shuffle/shuffle-shared@v0.9.95/shared.go:1167:11: sub.Id undefined (type PaymentSubscription has no field or method Id)
/Users/aditya/go/pkg/mod/github.com/shuffle/shuffle-shared@v0.9.95/shared.go:1175:29: org.Subscriptions[i].Id undefined (type PaymentSubscription has no field or method Id)
/Users/aditya/go/pkg/mod/github.com/shuffle/shuffle-shared@v0.9.95/shared.go:1176:27: org.Subscriptions[i].Id undefined (type PaymentSubscription has no field or method Id)
/Users/aditya/go/pkg/mod/github.com/shuffle/shuffle-shared@v0.9.95/shared.go:12569:3: unknown field Id in struct literal of type PaymentSubscription
/Users/aditya/go/pkg/mod/github.com/shuffle/shuffle-shared@v0.9.95/shared.go:12741:11: sub.Id undefined (type PaymentSubscription has no field or method Id)
/Users/aditya/go/pkg/mod/github.com/shuffle/shuffle-shared@v0.9.95/shared.go:12755:11: updated.Id undefined (type PaymentSubscription has no field or method Id)
/Users/aditya/go/pkg/mod/github.com/shuffle/shuffle-shared@v0.9.95/shared.go:12755:25: existing.Id undefined (type PaymentSubscription has no field or method Id)```