Renaming implementation-data-api module

[Jean-Sebastien Delfino]

I'd like to rename the implementation-data-api module to data-api, to 
reflect that it's not a component implementation type.

I'm planning to rename the package as well, but keep the current 
implementation.data package as well for backward compatibility.

I'd like to do that later this week, if there's no objections.
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Jean-Sebastien