intent: support share with Ring

ring-android/app/src/main/AndroidManifest.xml

.../app/src/main/java/cx/ring/adapters/SmartListAdapter.java

...pp/src/main/java/cx/ring/application/RingApplication.java

...pp/src/main/java/cx/ring/client/ConversationActivity.java

...ndroid/app/src/main/java/cx/ring/client/HomeActivity.java

...droid/app/src/main/java/cx/ring/client/ShareActivity.java

...oid/app/src/main/java/cx/ring/contacts/AvatarFactory.java

...a/cx/ring/dependencyinjection/RingInjectionComponent.java

...java/cx/ring/dependencyinjection/RingInjectionModule.java

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

...pp/src/main/java/cx/ring/fragments/ShareWithFragment.java

.../main/java/cx/ring/services/RingChooserTargetService.java

...oid/app/src/main/java/cx/ring/views/PreviewVideoView.java

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

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

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

...id/libringclient/src/main/java/cx/ring/model/Account.java

...t/src/main/java/cx/ring/smartlist/SmartListViewModel.java