cli: Add empty neofs-cli app structure

In the following release `neofs-cli` will be used to directly manage NeoFS Node.
All required definitions and interfaces are also moving from `neofs-api` to
`neofs-node` repository, so it's more convinient to have `neofs-cli` here.

Signed-off-by: Stanislav Bogatyrev <stanislav@nspcc.ru>

cmd/neofs-cli/main.go

@@ -0,0 +1,7 @@
+package main
+
+import cmd "github.com/nspcc-dev/neofs-node/cmd/neofs-cli/modules"
+
+func main() {
+	cmd.Execute()
+}