Add gocritic linter (#1324)

* Add gocritic linter

`gocritic` provides diagnostics that check for bugs, performance, and style issues

We disable the following checks:

- commentFormatting
- captLocal
- deprecatedComment

This PR contains many `//nolint:gocritic` to disable `appendAssign`.

management/server/http/policies_handler.go

@@ -300,7 +300,7 @@ func toPolicyResponse(account *server.Account, policy *server.Policy) *api.Polic
 			Action:        api.PolicyRuleAction(r.Action),
 		}
 		if len(r.Ports) != 0 {
-			portsCopy := r.Ports[:]
+			portsCopy := r.Ports
 			rule.Ports = &portsCopy
 		}
 		for _, gid := range r.Sources {