Move Google Login prompt higher, made it bigger

[snipe]

Makes the Google login button higher on the page and larger.

Fixes FB-39748

[what-the-diff]

PR Summary

• Creation of a New CSS Class
  A new CSS class named .separator was introduced. This class is used to style a separator with centrally-placed text. It's utilized on the login page of our app.

• Adjustments in Front-end Files to Accommodate .separator
  The styles specified in the .separator class were included in multiple CSS files such as app.css, all.css and in the less file overrides.less. These changes ensure the new characteristic defined by .separator can be accessed in various parts of our application.

• Revision in JSON and CSS Files
  The versions of overrides.css and app.css files recorded in mix-manifest.json were updated to reflect their modifications. Having up-to-date versions helps in easy identification and reduces conflict among various versions.

• Addition of New Translation
  The files auth/general.php and general.php were revised to include a new translation for the term "or". This change enhances our app's capability to cater to different user languages.

• Modification of Login Interface
  The login interface (login.blade.php file) now includes a Google login button. The .separator class has also been put to use here for better representation of the option "or", providing users a choice to log in either via their Google account or other means.