Locked / default content enhancements

[ghost]

• [x] Change edit locked content icon in admin bar
  replace it by this one instead:

• [x] "Set locked content (Post)" is displayed on 404 error page but it shouldn't

[ghost]

EDITED

[ghost]

• Don't use is_plugin_active() to check if a plugin is really available because it doesn't always work: example with Polylang Pro it breaks (because the path is polylang-pro/polylang.php). Only check for function_exists()

[ghost]

• To fix "Post-types" & "Taxonomies" which are duplicated sometimes with Polylang:
  • Function pll_set_post_language() must be call early otherwise it will regenerate another post for the default language:

[ghost]

• We could also duplicate the acf meta to automatically have the same layouts present in the translated posts / terms.