PLT-2555/PLT-5009/PLT-5225 Changed system messages to be rendered by the client (#5209)

* Moved rendering of (message deleted) into PostMessageView

* Added additional post types to constants on client

* Changed system messages to be rendered in the client's language

* Updated new system messages to have relevant usernames highlighted and have markdown rendered in header change messages

webapp/i18n/en.json

@@ -968,6 +968,18 @@
   "analytics.team.title": "Team Statistics for {team}",
   "analytics.team.totalPosts": "Total Posts",
   "analytics.team.totalUsers": "Total Users",
+  "api.channel.add_member.added": "{addedUsername} added to the channel by {username}",
+  "api.channel.delete_channel.archived": "{username} has archived the channel.",
+  "api.channel.join_channel.post_and_forget": "{username} has joined the channel.",
+  "api.channel.leave.left": "{username} has left the channel.",
+  "api.channel.post_update_channel_displayname_message_and_forget.updated_from": "{username} updated the channel display name from: {old} to: {new}",
+  "api.channel.post_update_channel_header_message_and_forget.removed": "{username} removed the channel header (was: {old})",
+  "api.channel.post_update_channel_header_message_and_forget.updated_from": "{username} updated the channel header from: {old} to: {new}",
+  "api.channel.post_update_channel_header_message_and_forget.updated_to": "{username} updated the channel header to: {new}",
+  "api.channel.remove_member.removed": "{removedUsername} was removed from the channel",
+  "app.channel.post_update_channel_purpose_message.removed": "{username} removed the channel purpose (was: {old})",
+  "app.channel.post_update_channel_purpose_message.updated_from": "{username} updated the channel purpose from: {old} to: {new}",
+  "app.channel.post_update_channel_purpose_message.updated_to": "{username} updated the channel purpose to: {new}",
   "audit_table.accountActive": "Account made active",
   "audit_table.accountInactive": "Account made inactive",
   "audit_table.action": "Action",

webapp/i18n/fr.json

@@ -968,6 +968,18 @@
   "analytics.team.title": "Statistiques d'équipe pour {team}",
   "analytics.team.totalPosts": "Nombre de messages",
   "analytics.team.totalUsers": "Nombre d'utilisateurs",
+  "api.channel.add_member.added": "{addedUsername} a été ajouté au canal par {username}",
+  "api.channel.delete_channel.archived": "{username} a archivé le canal.",
+  "api.channel.join_channel.post_and_forget": "{username} a rejoint le canal.",
+  "api.channel.leave.left": "{username} a quitté le canal.",
+  "api.channel.post_update_channel_displayname_message_and_forget.updated_from": "{username} a mis à jour l'en-tête du canal de : {old} en : {new}",
+  "api.channel.post_update_channel_header_message_and_forget.removed": "{username} a supprimé le titre du canal (était : {old})",
+  "api.channel.post_update_channel_header_message_and_forget.updated_from": "{username} a mis à jour l'en-tête du canal de : {old} en : {new}",
+  "api.channel.post_update_channel_header_message_and_forget.updated_to": "{username} a mis à jour l'en-tête du canal en : {new}",
+  "api.channel.remove_member.removed": "{removedUsername} a été retiré du canal.",
+  "app.channel.post_update_channel_purpose_message.removed": "{username} a supprimé le titre du canal (était : {old})",
+  "app.channel.post_update_channel_purpose_message.updated_from": "{username} a mis à jour l'en-tête du canal de : {old} en : {new}",
+  "app.channel.post_update_channel_purpose_message.updated_to": "{username} a mis à jour l'en-tête du canal en : {new}",
   "audit_table.accountActive": "Compte activé",
   "audit_table.accountInactive": "Compte désactivé",
   "audit_table.action": "Action",