Enable/disable mirroring captured pictures when using the front camera

[arjovanramshorst]

Is your feature request related to a problem? Please describe.
When people take selfies, they'd prefer if the image is mirrored (same way as it is shown by the camera while taking the picture). It seems like this is not possible right now.

Describe the solution you'd like
A property like: mirrorOnCapture: boolean, or something that fits with the package, that determines whether or not the captured image should be mirrored.

Describe alternatives you've considered
Manually processing the image in the frontend to mirror it, or render the image mirrored directly after capture, and actually mirror the image in the backend (both quite convoluted options for something that seems quite a standard feature, pretty much every app that uses the front camera does this by default)

Additional context
I'd be happy to provide a PR, but have very little experience with actual native code, if someone could point me in the direction where I could add this I could take a look.

[scarlac]

Which platform are you seeing this issue on? As it stands, on iOS, the viewfinder is mirroring, and the captured image is "normal". This selfie behavior matches what the native iOS camera does.