Feature request: Project translation for multi-languages

As a addition to gettext support for static page content support to multiple languages (see #10), it would be good to have also ability to add project description on current and different language.

Current situation
- site gettext is supporting English, Spanish and Croatian, but project description is always available in one language

Expected situation
- beside gettext translated site static content, project page should have language switch to enter content in different languages supported by site (in this specific case English, Spanish and Croatian). By doing this site visitor using English site GUI would read english project description, and site visitor using Croatian site GUI would read Croatian project description.

Review the existing gettext support and related issue #10 first; no files or tests are named in this issue. Done means project descriptions can be entered and displayed per supported language, with the project page's language choice selecting the matching content.

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