Maintenance: refactor servers updater code

- Require at least 80% of number of servers now to pass
- Each provider is in its own package with a common structure
- Unzip package with unzipper interface
- Openvpn package with extraction and download functions

internal/updater/providers/hidemyass/hosttourl.go

@@ -0,0 +1,37 @@
+package hidemyass
+
+import (
+	"context"
+	"net/http"
+	"strings"
+
+	"github.com/qdm12/gluetun/internal/updater/openvpn"
+)
+
+func getAllHostToURL(ctx context.Context, client *http.Client) (
+	tcpHostToURL, udpHostToURL map[string]string, err error) {
+	tcpHostToURL, err = getHostToURL(ctx, client, "TCP")
+	if err != nil {
+		return nil, nil, err
+	}
+
+	udpHostToURL, err = getHostToURL(ctx, client, "UDP")
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return tcpHostToURL, udpHostToURL, nil
+}
+
+func getHostToURL(ctx context.Context, client *http.Client, protocol string) (
+	hostToURL map[string]string, err error) {
+	const baseURL = "https://vpn.hidemyass.com/vpn-config"
+	indexURL := baseURL + "/" + strings.ToUpper(protocol) + "/"
+
+	urls, err := fetchIndex(ctx, client, indexURL)
+	if err != nil {
+		return nil, err
+	}
+
+	return openvpn.FetchMultiFiles(ctx, client, urls)
+}