Add routing for call page

Enable buttons to start a call.
Improve ConversationListItem context menu layout.
Move calling buttons from `Button.tsx` to `CallButtons.tsx`.
Add CallProvider

GitLab: #78
Change-Id: I921aa11383bf39fae18e59b01afb00dc66b0d5e6
diff --git a/client/src/locale/fr/translation.json b/client/src/locale/fr/translation.json
index 0da1c1a..0bc65b2 100644
--- a/client/src/locale/fr/translation.json
+++ b/client/src/locale/fr/translation.json
@@ -1,4 +1,11 @@
 {
+  "conversation_message": "Envoyer un message",
+  "conversation_start_audiocall": "Démarrer appel audio",
+  "conversation_start_videocall": "Démarrer appel vidéo",
+  "conversation_close": "Fermer la conversation",
+  "conversation_details": "Détails de la conversation",
+  "conversation_block_contact": "Bloquer le contact",
+  "conversation_delete_contact": "Supprimer le contact",
   "conversation_title_one": "{{member0}}",
   "conversation_title_two": "{{member0}} et {{member1}}",
   "conversation_title_three": "{{member0}}, {{member1}} et {{member2}}",