Delete duplicate readme
Delete duplicate readme

Fix having wwo readmes w/same content, causes git warnings on case-insensitive file systems.
gsuitedevs/hangouts-chat-samples,googleworkspace/hangouts-chat-samples,googleworkspace/hangouts-chat-samples,gsuitedevs/hangouts-chat-samples,gsuitedevs/hangouts-chat-samples,gsuitedevs/hangouts-chat-samples,googleworkspace/hangouts-chat-samples,googleworkspace/hangouts-chat-samples