Generate GraphQL code for JS/TS

[Gerharddc]

The GraphQL operations file that can currently be generated using the "graphql" type is not useable with JS/TS as far as I know. When using the codegen feature of the Amplify CLI, three different files (mutations.ts, queries.ts and subscriptions.ts) are generated which contain the same operations as the file that this plugin generates but as strings. It would be great if this plugin could generate those files or at least one file with the operations as strings.