Add Android support

[Jerakin]

Maybe this is relevant
https://developer.android.com/guide/topics/providers/document-provider.html

[andsve]

Sounds like a good idea!

I wonder if Android would let us just return the URI back to Lua then at a later step actually load the data at that URI, or if it needs to be done in one step? If it is just possible to return the URI and load the content later on the implementation should be quite easy.

However, I'm not sure if it can be used for diags.save()? Will have to investigate.