Add ES-C51 (Expected Sarsa based C51)#529

Rijul-Tandon wants to merge 11 commits intovwxyzjn:mastervwxyzjn/cleanrl:masterfrom

Rijul-Tandon:feature/es-c51-algorithmRijul-Tandon/cleanrl_ES-C51:feature/es-c51-algorithmCopy head branch name to clipboard