Refactor file transfer to take in xxdk.e2e

bindings/fileTransfer.go

cmd/fileTransfer.go

fileTransfer/connect/params.go

fileTransfer/connect/send.go

fileTransfer/connect/utils_test.go

fileTransfer/connect/wrapper.go

fileTransfer/connect/wrapper_test.go

fileTransfer/e2e/send.go

fileTransfer/e2e/utils_test.go

fileTransfer/e2e/wrapper.go

fileTransfer/e2e/wrapper_test.go

fileTransfer/groupChat/send.go

fileTransfer/groupChat/utils_test.go

fileTransfer/groupChat/wrapper.go

fileTransfer/groupChat/wrapper_test.go

fileTransfer/manager.go

fileTransfer/manager_test.go

fileTransfer/utils_test.go