Move metadata, codegen and java lib into the new repo.

[copybara-service]

Move metadata, codegen and java lib into the new repo.

[lutzroeder]

@xunkai55 why was this code removed from the TensorFlow main repository before this PR was merged.

[xunkai55]

@xunkai55 why was this code removed from the TensorFlow main repository before this PR was merged.

We got some problem in code migration process. Will resolve the problem soon

[lutzroeder]

Would it make sense to keep metadata_schema.fbs in the TensorFlow repo? It's not worth the extra effort tracking another repository and leaning towards removing support. Wasn't the goal to include this with the official TensorFlow Lite schema?

[xunkai55]

@lutzroeder Thanks for your suggestion. May I know more about your use cases? E.g. When you use the metadata_schema.fbs, what kind of tools you also use to consume it?

It would help us better decide if we should keep a copy in main TF repo. Thanks!

[lutzroeder]

See tensorflow/tensorflow#39109

@lu-wang-g

[lu-wang-g]

@lutzroeder it is true that we do have the future vision of the merging the metadata schema with the TFLite schema, but the plan is not concrete yet. At least for now, the metadata library is an important component of the TFLite Support library, and it is released through the Support library package for each version, not through the TF/TFLite package.