Add support for LlamaCloud (#554)

.changeset/angry-pugs-tap.md

apps/docs/docs/modules/llamacloud.mdx

examples/cloud/README.md

examples/cloud/chat.ts

examples/cloud/query.ts

packages/core/package.json

packages/core/src/cloud/LlamaCloudIndex.ts

packages/core/src/cloud/LlamaCloudRetriever.ts

packages/core/src/cloud/index.ts

packages/core/src/cloud/types.ts

packages/core/src/cloud/utils.ts

packages/core/src/index.ts

packages/eslint-config-custom/index.js

pnpm-lock.yaml