Add case study: Booking.com (#20783)

* Create index.html

* add logos

* fix logo file name

* add booking.com images

* remove Nav from featured

* add booz allen featured logo

* make Booz Allen featured

* remove spotify from featured

* fix booz allen front matter

* add correct logo

* add correct booz allen logo

content/en/case-studies/booz-allen/index.html

@@ -4,7 +4,11 @@ linkTitle: booz-allen
 case_study_styles: true
 cid: caseStudies
 css: /css/case-studies-gradient.css
-featured: false
+logo: booz-allen_featured_logo.png
+featured: true
+weight: 2
+quote: >
+  Kubernetes is a great solution for us. It allows us to rapidly iterate on our clients’ demands.
 ---
 ​