Separate out theming into its own pacakge.

[flyingcircle]

Theming in RNE is unique in that I don't know of any other theming package in React Native that handles theming the way we do. Unfortunately however, during the move to typescript, it became clear that reasoning around the types for theming is complicated, and any user of RNE that doesn't want to use themes has an unnecessary added layer of complexity.

My suggestion here is that for RNE 5.0, we remove theming and extract out into its own pacakge react-native-elements-themed. Can anyone think of pros/cons to this?

CC: @Monte9 @pranshuchittora @arpitBhalla @khushal87

Or perhaps if we continue to expand the number of packages in RNE we should start scoping the package names: @react-native-elements/base @react-native-elements/themed etc.

[arpitBhalla]

Will @react-native-elements/themed be components of @react-native-elements/base with a HOC of withTheme?

[flyingcircle]

Yeah that's my thinking. Basically pull out the default HOC, and have a separate package where that is added to the components.

[arpitBhalla]

Can we export un-themed components from another sub directory?

Edit: And this, within the same package

[flyingcircle]

Well, part of my hope was to simplify the code a bit. Just exporting the components to another package may be simpler to implement, but it doesn't simplify the code.