BottomBar Styling

[aakashs007]

Bottom bar styling should be allowerd more options. There is only specific css allowed right now.

[aadelgrossi]

@aakashs007 I created a fork and added a StyleProp to the bottom bar objects along with some other changes, hopefully making room for more customization. https://github.com/aadelgrossi/react-native-onboarding-swiper

What I did notice is that regardless of showSkip being false, empty space was being rendered on the left side. I updated this behavior to render only the pagination dots (which i needed all the way to the left) and next button on the right.

If you still want dots in the center but no skip, either padding or bottom bar width CSS can be tweaked via the new bottomBarStyles property.

This still doesn't cover advanced use cases and alignments such as having dots to the left, and next button + skip stacked vertically. I wonder adding CSS overrides for all three components (next, dots and skip) individually is overkill or could be helpful for other styling purposes, but I couldn't find a reason to do that.

@jfilter if these changes make sense, let me know so I can PR them in the main repo. I'd appreciate your remarks and comments on this as well.

[jotilohana]

@aadelgrossi can you please tell me how to customize bottom color