feat(posters): add original poster images to README files

Added sections for displaying original posters in the README files of 5th-step, hamlet, and mr-burton directories. This change includes images and links to improve visual documentation and reference for the marketing materials associated with each project.

5th-step/README.md

@@ -4,6 +4,10 @@
 
 All NT marketing materials are available [here](https://nationaltheatrelive.egnyte.com/fl/6dMyp6wjkmfV)
 
+## [original poster(5th-A3-1.jpg)](5th-A3-1.jpg)
+
+![original poster](5th-A3-1.jpg)
+
 ## [rose ash poster(5th-final.jpg)](5th-final.jpg)
 
 ![poster](5th-final.jpg)

hamlet/README.md

@@ -4,6 +4,9 @@
 
 All NT marketing materials are available [here](https://nationaltheatrelive.egnyte.com/fl/xwH93vMf7yBm)
 
+## [original poster(hamlet-landscape.jpg)](hamlet-landscape.jpg)
+
+![original poster](hamlet-landscape.jpg)
 
 ## [rose ash poster(hamlet-final.jpg)](hamlet-final.jpg)
 

mr-burton/README.md

@@ -2,6 +2,11 @@
 
 [rose-ash.com](https://rose-ash.com/mr-burton/)
 
+
+## [original poster(burton-original.jpg)](burton-original.jpg)
+
+![original poster](burton-original.jpg)
+
 ## [rose ash poster(burton.jpg)](burton.jpg)
 
 ![poster](burton.jpg)