Better defaults for .graphqlconfig.yml

**Is your feature request related to a problem? Please describe.**
Amplify codegen dumps it's graphql all over the place like an itinerant toddler.

**Describe the solution you'd like**
Dump all the generated code for an api in a folder named for the API

```yaml
projects:
{ApiName}:
schemaPath: src/{ApiName}/schema.json
includes:
- src/{ApiName}/**/*.ts
excludes:
- ./amplify/**
- src/{ApiName}/types.ts
extensions:
amplify:
codeGenTarget: typescript
generatedFileName: src/{ApiName}/types.ts
docsFilePath: src/{ApiName}
extensions:
amplify:
version: 3
```

There could even be some barrels for importing convenience
```typescript
// {ApiName}/index.ts
export * from './mutations'
export * from './queries'
export * from './subscriptions'
export * from './types'
```

```typescript
// index.ts
export * as {ApiName} from './ {ApiName}'
```