[i18n] Translation issues

[marcinkunert]

Version:

• listmonk: v2.1.0
• OS: Docker

There are few translation issues I've found:

• site titles are not translatable (Dashboard / Lists / Subscribers etc.)
• on overview (/admin/) the Campaign views chart shows "Link clicks" when hovering over the chart
• /admin/lists uses singular form for subscriber count types (e.g. subscribers.status.unconfirmed) but should use plural form (in English adjectives doesn't have singular or plural form, so both Status: Unconfirmed and Unconfirmed 165 makes sense, but in Polish unfortunately not. I believe in German it should be Status: Angemeldet but with count: Angemeldete: 165)
• /admin/campaigns - campaign duration is not translatable (e.g. 5 Minutes)
• /admin/campaigns/media - months (media seem to be grouped by months)