chore(publicip): refactoring

- Exported `Fetcher` interface
- Inject `Fetcher` to publicip loop and updaters
- Get public IP and information at the same time
- Only query ipinfo.io
- Make `MultiInfo` part of the `Fetch` object

internal/publicip/models/ipinfo.go

@@ -3,7 +3,7 @@ package models
 import "net"
 
 type IPInfoData struct {
-	IP       net.IP `json:"public_ip"`
+	IP       net.IP `json:"ip,omitempty"`
 	Region   string `json:"region,omitempty"`
 	Country  string `json:"country,omitempty"`
 	City     string `json:"city,omitempty"`
@@ -20,8 +20,3 @@ func (i IPInfoData) Copy() (copied IPInfoData) {
 	copy(copied.IP, i.IP)
 	return copied
 }
-
-func (i *IPInfoData) SetIP(ip net.IP) {
-	i.IP = make(net.IP, len(ip))
-	copy(i.IP, ip)
-}