Optimization: reduce asset catalog size in extensions

[kean]

The app extensions include the same asset catalogs that the app does, which has the following negative effects:

1. The catalog gets compiled multiple times. There is an opportunity to reduce the build time by 10 seconds.

2. The catalog is included in every extension, significantly increasing their size.

[jkmassel]

@kean – I think you've done this now, right?

[kean]

Not yet. The catalog is much smaller now, so the size is no longer a major concern, but the compile time is likely still is.