[expo-updates][README] remove embedded asset paths from app.json setup instructions and make setup instructions more self-hosting-centric
[expo-updates][README] remove embedded asset paths from app.json setup instructions and make setup instructions more self-hosting-centric

exponent/exponent,exponent/exponent,exponentjs/exponent,exponent/exponent,exponent/exponent,exponentjs/exponent,exponentjs/exponent,exponent/exponent,exponentjs/exponent,exponentjs/exponent,exponentjs/exponent,exponent/exponent,exponent/exponent,exponent/exponent,exponentjs/exponent,exponentjs/exponent,exponentjs/exponent,exponent/exponent