Implement Protobuf classes in Android

[cereallarceny]

We need to add the following Protobuf classes to KotlinSyft as they are completed:

• Plan
• State
• Operation
• Placeholder
• TorchParameter
• Protocol
• PromiseTensor

Stories associated to this epic:

• Infrastructure Protobuf infrastructure #43

[vkkhare]

@all-contributors add @mccorby for doing tests

[allcontributors]

@vkkhare

I've put up a pull request to add @mccorby! 🎉