Convert the tagline under logo to text
Optimize all image assets

Why did no one do that earlier?
Merge branch 'dev' of https://github.com/monterail/otwartezabytki into dev

* 'dev' of https://github.com/monterail/otwartezabytki:
  fix: new version of rails-i18n resolve pluralization problems and includes proper polish pluralizations
  fix: add last edited partial
  fix: set detected language from browser locales in language select
  feature: group links by relic name
  feature: show dates and animate last versions
  enable polish and english locale
  add alert redirect to relic after created, adding missing i18n
  fix: do not hide the translation window
  filter labels fix
  widgets login
  map widget fixes
  hide information about filled relics
  cc-by icon
  choose locale according browser language
  locale pl.yml production sync
  add i18n yml translations
  remove unused deprecated partials
  Revert "add link to competition"