New pages: - `about/website` - `about/logo` _(for pl, ru: only small update)_ Changes in `_config.yml`: - update `credits` - <del>remove `logo_credit`</del> Status: - [x] bg - [x] de - [ ] es - [ ] fr - [x] id - [x] it - [x] ja - [x] ko - [ ] pl - [x] pt - [ ] ru - [ ] tr - [ ] vi - [x] zh_cn - [x] zh_tw