Add a license statement in the footer (#637)

mike

30.25.2022 720271a5bf72404ac60aa619ffdc7e4276952e8d

 i18n/zh-tw.toml

@@ -30,6 +30,9 @@
[head_back]
other = "返回 <a href=\"{{ . }}\">首頁</a>."

[licensed_under]
other = "Licensed under"

[powered_by]
other = "技術支援"