Expose imageStyle prop

[alexandreh92]

Hi, thanks for this repo. This is an awesome contribuiton.

I'm wondering if we can expose a new prop named imageStyle, which will append to the existing styles.image.

With this new prop we can customize the resizeMode, aspecRatio and other Image specific props.

I'm openining a PR to handle this.

[efstathiosntonas]

@alexandreh92 closing this due to inactivity, feel free to reopen