HomeActivity: support foldable devices

...p/src/main/java/cx/ring/account/AccountEditionFragment.kt

...c/main/java/cx/ring/account/JamiAccountSummaryFragment.kt

.../app/src/main/java/cx/ring/client/ConversationActivity.kt

...-android/app/src/main/java/cx/ring/client/HomeActivity.kt

...n/java/cx/ring/contactrequests/ContactRequestsFragment.kt

...p/src/main/java/cx/ring/fragments/ConversationFragment.kt

.../app/src/main/java/cx/ring/fragments/SmartListFragment.kt

.../src/main/java/cx/ring/interfaces/BackHandlerInterface.kt

...id/app/src/main/java/cx/ring/settings/SettingsFragment.kt

...android/app/src/main/res/layout-sw600dp/activity_home.xml

...android/app/src/main/res/layout/activity_conversation.xml

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

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

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

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