chore(medusa,admin-ui): Add reservations FF (#4184)

* chore(medusa,admin-ui): Add reservations FF

* Create five-ways-care.md

* Tweak description

packages/medusa/src/loaders/feature-flags/reservations.ts

@@ -0,0 +1,10 @@
+import { FlagSettings } from "../../types/feature-flags"
+
+const ReservationsFeatureFlag: FlagSettings = {
+  key: "reservations",
+  default_val: false,
+  env_key: "MEDUSA_FF_RESERVATIONS",
+  description: "[WIP] Enable the reservations feature from the Inventory Module",
+}
+
+export default ReservationsFeatureFlag