I18n health warnings (#1949)

* Rename admin.domain_block to admin.domain_blocks in prep for i18n improvement

* Use implicit controller/action path for i18n in admin/domain_blocks

* Add DomainBlock#accounts has_many

* Avoid i18n health warning for `en` locale by using symbol scope with :count

* Remove unused i18n key: plaintext_secret_html

* Remove unused i18n key two_factor_auth.warning

* Remove final will_paginate i18n keys

* Remove unused key two_factor_auth.recovery_codes

* Remove unused key: admin.reports.comment.none

* Remove unused reports. i18n namespace (moved to admin.reports)

* Ignore keys from locales which override activemodel and activerecord errors

* Revert "Remove unused key: admin.reports.comment.none"

This reverts commit 350ef2685fadc069e619bb6d1066190de195d942.

* Update i18n key reference to match moved location

* Add missing `en` keys to i18n

* Tell i18n-tasks to ignore missing attributes that dont need overwriting

* Add i18n-tasks unused to travis

config/locales/hr.yml

@@ -156,8 +156,6 @@ hr:
     disable: Onemogući
     enable: Omogući
     instructions_html: "<strong>Skeniraj ovaj QR kod into Google Authenticator or a similiar app on your phone</strong>. Od sada, ta aplikacija će generirati tokene koje ćeš unijeti pri prijavljivanju."
-    plaintext_secret_html: 'Plain-text secret: <samp>%{secret}</samp>'
-    warning: Ako trenuno ne možeš konfigurirati authenticator app, trebaš kliknuti "onemogući" ili se nećeš moći prijaviti.
   users:
     invalid_email: E-mail adresa nije valjana
     invalid_otp_token: Nevaljani dvo-faktorski kod