ui: update "About" page

...id/app/src/main/java/cx/ring/fragments/AboutFragment.java

ring-android/app/src/main/res/drawable-hdpi/ring_logo.png

ring-android/app/src/main/res/drawable-mdpi/ring_logo.png

ring-android/app/src/main/res/drawable-xhdpi/ring_logo.png

ring-android/app/src/main/res/drawable-xxhdpi/ring_logo.png

ring-android/app/src/main/res/drawable-xxxhdpi/ring_logo.png

ring-android/app/src/main/res/layout/frag_about.xml

ring-android/app/src/main/res/values-fr/strings.xml

ring-android/app/src/main/res/values/strings.xml