Add ability to align FAB group

[jamenamcinteer]

Is your feature request related to a problem? Please describe.
For my use case, I need the Fab group to be align to the bottom left of the screen instead of the bottom right. I am currently using patch-package to hack it, but it would be great to have this added to react-native-paper.

Describe the solution you'd like
Add an "align" property to Fab.Group to align the group to the left or center instead of just the right.

Describe alternatives you've considered
Using patch-package, but it requires changing the patch every time I need to upgrade the package to a new version.

Additional context
N/A

I would be happy to work on a PR for this if it's ok to introduce something like this.