[Monorepo] Move pods to the root level and add bundles

[dratwas]

Description

This is a part of migration gutenberg-mobile to gutenberg repo.

In this PR I moved Gutenberg.podspec and RNAztecView.podspec to the root directory since the podspec file is expected to be in the root of the repo. I also updated JS bundles.

How has this been tested?

• change repo url to gutenberg one in Podfile (Wordpress-iOS)
• set the last commit from this PR in Podfile(Wordpress-iOS)
• run rake dependencies
• dependencies should be installed without errors

Types of changes

Move podspec files to the root level.

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.
• I've updated all React Native files affected by any refactorings/renamings in this PR. .