[Tooling] Standardize podspec format

As part of paaHJt-Vl-p2, this simply standardize the podspec file so that all our pods use a similar format and structure, with similar keys and common values.

See wordpress-mobile/WordPressAuthenticator-iOS#582 for the rules I decided to follow on the format and content standardization.

Notes

This contains changes to 2 (two) podspecs at once – WordPress-Aztec-iOS and WordPress-Editor-iOS – since those are related and hosted in that same single repo.
It appears that this repository has been renamed a while ago – and indeed the old https://github.com/wordpress-mobile/WordPress-Aztec-iOS URL redirects to https://github.com/wordpress-mobile/AztecEditor-iOS – so I've also updated the s.source and s.homepage of those 2 podspecs accordingly.

wordpress-mobile / AztecEditor-iOS

[Tooling] Standardize podspec format #1329

Notes