Remove `regions` from Progrqam GraphQL Schema and Resolvers

[joneubank]

Regions are being replaced by data centers in the programs data model. To prep for this we will remove regions from the gateway.

This ticket should be done along side icgc-argo/platform-ui#2724 which makes similar changes to the UI. There is a cross dependency on the regions field in the create and update program methods, so changes will need to be deployed to UI and API at the same time.

Detailed Description

• Remove regions from the program type in the GQL schema
• Remove regions references in the program resolvers

[demariadaniel]

Regions need to be replaced by dataCenters
Causing bug in context with Create Program / Update Program operations
cc: @joneubank