Review branding in-app

[Jaifroid]

Following a recent team meeting, branding decisions for the Kiwix JS apps were recorded in the Branding document.

This issue is about reviewing the branding internally in the app. Mostly, this should simply be "Kiwix", but it is acceptable to use qualifications such as "Kiwix JS" or related if emphasizing the difference between this app and the native apps, or between Kiwix JS packaged for Browser Extensions and the PWA version, for example.

Most branding in-app appears in the About page. Some appears on Configuration and Home.