feat: Support glob pattern and absolute path for schema

[h-kishi]

Support both glob pattern and absolute path for schema.

custom:
  appSync:
    schema:
      - path/**/*.graphql
      - /path/to/schema.graphql

Since all schemas are passing through mergeTypes by my implementation, the snapshot has changed a lot.

[bboure]

Awesome!! Thank you @h-kishi This is a long-waited feature!