[skip ci] Added translations for RelativeTime

[skip ci] Update security-authentication.md

Minor syntax change.

Added relative time translations

Update output-theming.md

Minor syntax changes.

Additional minor syntax changes.

[skip ci] Update output-data-widgets.md

Minor syntax changes.

[skip ci] Update output-formatter.md

[skip ci] Update input-file-upload.md

Minor syntax changes.

Docs guide ja intro revised　[ci skip]

Docs guide ja start revised [ci skip]

docs/guide-ja/intro-upgrade-from-v1.md - revised using "初期設定" and "設定情報" for "configuration(s)" [ci skip]

Fixes #5480: Added defensive code to `yii\web\User::getIdentity()` to avoid potential infinite recursion