Remove Gradle cheatsheet
Remove Gradle cheatsheet

We are long past the Maven to Gradle transition, and Gradle is
commonplace enough these days that we do not need to devote a top-level
file on a Gradle cheatsheet.

Relates #28113

robin13/elasticsearch,robin13/elasticsearch,HonzaKral/elasticsearch,uschindler/elasticsearch,gingerwizard/elasticsearch,uschindler/elasticsearch,scottsom/elasticsearch,s1monw/elasticsearch,scorpionvicky/elasticsearch,fred84/elasticsearch,gfyoung/elasticsearch,nknize/elasticsearch,GlenRSmith/elasticsearch,coding0011/elasticsearch,kalimatas/elasticsearch,robin13/elasticsearch,kalimatas/elasticsearch,qwerty4030/elasticsearch,qwerty4030/elasticsearch,gingerwizard/elasticsearch,coding0011/elasticsearch,gingerwizard/elasticsearch,HonzaKral/elasticsearch,s1monw/elasticsearch,qwerty4030/elasticsearch,scottsom/elasticsearch,scorpionvicky/elasticsearch,fred84/elasticsearch,kalimatas/elasticsearch,uschindler/elasticsearch,coding0011/elasticsearch,qwerty4030/elasticsearch,s1monw/elasticsearch,nknize/elasticsearch,rajanm/elasticsearch,kalimatas/elasticsearch,rajanm/elasticsearch,nknize/elasticsearch,GlenRSmith/elasticsearch,coding0011/elasticsearch,fred84/elasticsearch,scorpionvicky/elasticsearch,robin13/elasticsearch,fred84/elasticsearch,gfyoung/elasticsearch,gingerwizard/elasticsearch,scorpionvicky/elasticsearch,gfyoung/elasticsearch,qwerty4030/elasticsearch,nknize/elasticsearch,gfyoung/elasticsearch,GlenRSmith/elasticsearch,rajanm/elasticsearch,coding0011/elasticsearch,HonzaKral/elasticsearch,gingerwizard/elasticsearch,uschindler/elasticsearch,GlenRSmith/elasticsearch,rajanm/elasticsearch,kalimatas/elasticsearch,rajanm/elasticsearch,gfyoung/elasticsearch,scorpionvicky/elasticsearch,scottsom/elasticsearch,scottsom/elasticsearch,nknize/elasticsearch,HonzaKral/elasticsearch,gingerwizard/elasticsearch,fred84/elasticsearch,GlenRSmith/elasticsearch,rajanm/elasticsearch,scottsom/elasticsearch,gingerwizard/elasticsearch,robin13/elasticsearch,s1monw/elasticsearch,s1monw/elasticsearch,uschindler/elasticsearch