201-api-management-create-all-resources uses the Standard pricing tier value as default

[201-api-management-create-all-resources](https://github.com/Azure/azure-quickstart-templates/tree/master/201-api-management-create-all-resources)

### Issue Details
The example sets the pricing tier to Standard. This results an immediate large cost when the example is used. It would be better for the Developer pricing tier to be the default value.

### Repro steps (*if necessary, delete otherwise*)
1. Check-out example
2. Use default sku value
3. Watch your bill jump!

Open the 201-api-management-create-all-resources example and locate the default SKU or pricing-tier value. Change the default from Standard to Developer, then verify that using the example without changing the SKU selects the Developer tier and avoids the stated cost issue.

Written by the indexing model from the issue text.