i18n: Add Japanese translations for new landing page (#10254)

* yarn manage:translations && i18n-tasks add-missing

* Update Japanese translations for new landing page.

I don't change the tagline from English yet.
I think that translating a tagline is difficult and requires time-consuming discussions.

Some translations related about the poll are already done in Weblate, so I will leave it as it is.

app/javascript/mastodon/locales/defaultMessages.json

@@ -17,6 +17,10 @@
       {
         "defaultMessage": "File upload limit exceeded.",
         "id": "upload_error.limit"
+      },
+      {
+        "defaultMessage": "File upload not allowed with polls.",
+        "id": "upload_error.poll"
       }
     ],
     "path": "app/javascript/mastodon/actions/compose.json"
@@ -907,6 +911,52 @@
     ],
     "path": "app/javascript/mastodon/features/compose/components/navigation_bar.json"
   },
+  {
+    "descriptors": [
+      {
+        "defaultMessage": "Add a poll",
+        "id": "poll_button.add_poll"
+      },
+      {
+        "defaultMessage": "Remove poll",
+        "id": "poll_button.remove_poll"
+      }
+    ],
+    "path": "app/javascript/mastodon/features/compose/components/poll_button.json"
+  },
+  {
+    "descriptors": [
+      {
+        "defaultMessage": "Choice {number}",
+        "id": "compose_form.poll.option_placeholder"
+      },
+      {
+        "defaultMessage": "Add a choice",
+        "id": "compose_form.poll.add_option"
+      },
+      {
+        "defaultMessage": "Remove this choice",
+        "id": "compose_form.poll.remove_option"
+      },
+      {
+        "defaultMessage": "Poll duration",
+        "id": "compose_form.poll.duration"
+      },
+      {
+        "defaultMessage": "{number, plural, one {# minute} other {# minutes}}",
+        "id": "intervals.full.minutes"
+      },
+      {
+        "defaultMessage": "{number, plural, one {# hour} other {# hours}}",
+        "id": "intervals.full.hours"
+      },
+      {
+        "defaultMessage": "{number, plural, one {# day} other {# days}}",
+        "id": "intervals.full.days"
+      }
+    ],
+    "path": "app/javascript/mastodon/features/compose/components/poll_form.json"
+  },
   {
     "descriptors": [
       {
@@ -1853,6 +1903,10 @@
       {
         "defaultMessage": "{name} boosted your status",
         "id": "notification.reblog"
+      },
+      {
+        "defaultMessage": "Your poll has ended",
+        "id": "notification.poll"
       }
     ],
     "path": "app/javascript/mastodon/features/notifications/components/notification.json"
@@ -1914,24 +1968,6 @@
     ],
     "path": "app/javascript/mastodon/features/reblogs/index.json"
   },
-  {
-    "descriptors": [
-      {
-        "defaultMessage": "A look inside...",
-        "id": "standalone.public_title"
-      }
-    ],
-    "path": "app/javascript/mastodon/features/standalone/community_timeline/index.json"
-  },
-  {
-    "descriptors": [
-      {
-        "defaultMessage": "A look inside...",
-        "id": "standalone.public_title"
-      }
-    ],
-    "path": "app/javascript/mastodon/features/standalone/public_timeline/index.json"
-  },
   {
     "descriptors": [
       {