Added entity upload support

[sammyrulez]

I added support for entity upload, useful to load data from local or external systems.

[awal11]

Any progress on this? I just wanted to fetch the Developer Entities and reimplemented parts of the functionality myself, but now I see parts have been already done by @sammyrulez .
@sammyrulez two remarks

1. The class AIDataService defines constants for REQUEST_METHOD_POST = "POST" and "GET" so you should use them
2. Method that does a "POST" request to upload data probably should not be named getEntitiesAiResponse

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[awal11]

Not sure if this relates to me, but "I signed the CLA" just in case :-)