'any' type is supported starting from Go1.18. Let's consistently use it
instead of 'interface{}' type across the code base, since `any` is easier to read than 'interface{}'.
It is better developing vmctl tool in VictoriaMetrics repository, so it could be released
together with the rest of vmutils tools such as vmalert, vmagent, vmbackup, vmrestore and vmauth.
