Create a simple tool for finding missing translations

[ssddanbrown]

The current issue

Now that we have a great set of translations we need to make it easy for any translators to find strings that have not yet been updated. Currently, It's not much of an issue but as we get more translations and as new features are added with more text then translations will become further out of line.

Proposed solution

It would be great to have a simple command-line php script that can be ran which outputs which translations are missing or have been removed when compared to the english text.

This script would be located in the resources/lang folder but would be standalone and not rely on Laravel.
I'd imagine the call signature would be something like this:

php resources/lang/check-translations fr

And the output would be something like this:

Checking translations for 'fr'....

Missing 2 translations strings:
entities.permissions_intro
errors.permissionJson

The following 1 translation can be removed:
common.no_activity