Open the composer full screen, as a setting (#401) (#404)

Settings > General > Composing has a new switch, "Open the composer full
screen". With it on, every new composer, whether a new message, reply,
forward or reopened draft, starts maximized. Restore still shrinks it to
a window. A draft put back after an undone or failed send keeps the size
it had. It's off by default, and on a phone, where the composer already
fills the screen, it changes nothing.

One new string, translated in all nine catalogs. The count falling back
to English stays at 16 in every language.

Fixes #401

web/src/locales/ja.ts

@@ -749,6 +749,7 @@ export const catalog: Catalog = {
     "Attachment reminder": "添付忘れの確認",
     "Warn when the message mentions an attachment but none is attached.": "本文で添付に触れているのにファイルが添付されていないとき警告します。",
     "Spell check while typing": "入力中にスペルチェックする",
+    "Open the composer full screen": "メールを全画面で作成",
     "Confirm before deleting": "削除前に確認する",
     "Show message snippets": "本文の抜粋を表示する",
     "Preview the first line of each message in the list.": "一覧に各メールの 1 行目を表示します。",