easier access to the bundle schema

[wyli]

Is your feature request related to a problem? Please describe.
currently the schema file is at https://github.com/Project-MONAI/MONAI-extra-test-data/releases/tag/0.8.1, would be great to have an alias of them under the domain https://monai.io, such as https://monai.io/bundle/schema_draft/1.0.json