Extract i18n string into i18n/_defaults (base of translations) (#4514)

* Build script to pull i18n into i18n/_default

* Fix header

* Current strings as extracted

* details_windows without prefix

* clean before build

* Alwasy extract babel strings

* clean & run build before extraction

* Update settings messages

* Put back template string (PR comment)

* PR comment cleanups & logging

* Less complicated string type check (PR comment)

* Remove node cache to extract all keys (Thanks @ngotchac)

* Merge in defaults from i18n/en (Comment by @h3ll0fr13nd)

* Unique index keys only

* Update with latest master strings

* _.defaultsDeep (Thanks to @dehurst)

* Use to-source for string formatting

* Sync with toSource output on latest master

* Updated to use/output sorted objects