channel-specs remove unused fields for v1 (#347)

Part of shop/issues-multi-channel-management#1966
This PR updates the channel configuration specifications templates

### Checklist

- [x] I have 🎩'd these changes
- [x] I have squashed my commits into chunks of work with meaningful commit messages

Author: Fernanda-Montiel

channel-config/specifications/example-de.toml

@@ -7,8 +7,6 @@ productFeedManagement = "manual"
 bundles = true
 digitalProducts = true
 subscriptions = false
-variantModel = "products"
-multiLocationInventory = true
 combinedListings = true
 unlistedProducts = true
 

channel-config/specifications/example-us.toml

@@ -7,8 +7,6 @@ productFeedManagement = "automatic"
 bundles = true
 digitalProducts = true
 subscriptions = false
-variantModel = "products"
-multiLocationInventory = true
 combinedListings = true
 unlistedProducts = true
 
@@ -21,4 +19,4 @@ code = "US"
 languages = [
   "en"
 ]
-currency = "USD"
+currency = "USD"