feat(core-flows,medusa,types): fulfillment API: create (#7101)

what:

- adds fulfillment create API

RESOLVES CORE-1962

.changeset/new-dingos-impress.md

@@ -0,0 +1,7 @@
+---
+"@medusajs/core-flows": patch
+"@medusajs/medusa": patch
+"@medusajs/types": patch
+---
+
+feat(core-flows,medusa,types): add create shipment api for fulfillments

.changeset/strong-crabs-leave.md

@@ -0,0 +1,7 @@
+---
+"@medusajs/core-flows": patch
+"@medusajs/medusa": patch
+"@medusajs/types": patch
+---
+
+feat(core-flows,medusa,types): fulfillment API: create