refactor: rename directory `core` to `llamaindex` (#936)

.github/workflows/publish.yml

.github/workflows/publish_github.yml

.github/workflows/test.yml

CONTRIBUTING.md

README.md

apps/docs/docusaurus.config.js

packages/autotool/tsconfig.json

packages/community/tsconfig.json

packages/experimental/tsconfig.json

packages/llamaindex/.gitignore

packages/llamaindex/.madgerc

packages/llamaindex/CHANGELOG.md

packages/llamaindex/CONTRIBUTING.md

packages/llamaindex/e2e/.gitignore

packages/llamaindex/e2e/CHANGELOG.md

packages/llamaindex/e2e/README.md

packages/llamaindex/e2e/examples/README.md

...lamaindex/e2e/examples/cloudflare-worker-agent/.gitignore

...maindex/e2e/examples/cloudflare-worker-agent/CHANGELOG.md

...maindex/e2e/examples/cloudflare-worker-agent/package.json