Check Gitaly when running `rake dev:setup`

Before this change, trying to setup dev environment could be tried
without having at least one Gitaly running. Cloning the repositories
would fail, but not stop the setup.

Given this would lead to an inconsistent state, a check was added if we
could connect to the server.

Output when it fails:

```
$ rake dev:setup
Failed to connect to Gitaly...
Error: 14:Connect Failed
```

lib/tasks/gitlab/setup.rake

 namespace :gitlab do
   desc "GitLab | Setup production application"
   task setup: :gitlab_environment do
+    check_gitaly_connection
     setup_db
   end
 
+  def check_gitaly_connection
+    Gitlab.config.repositories.storages.each do |name, _details|
+      Gitlab::GitalyClient::ServerService.new(name).info
+    end
+  rescue GRPC::Unavailable => ex
+    puts "Failed to connect to Gitaly...".color(:red)
+    puts "Error: #{ex}"
+    exit 1
+  end
+
   def setup_db
     warn_user_is_not_gitlab