Windscribe API and more servers filter options, fixes #197 (#282)

- Use Windscribe API to fetch servers information
- More data on servers about region, city and hostname
- Add optional server filters with `REGION`, `CITY` and `HOSTNAME` csv environment variables

internal/settings/openvpn_test.go

@@ -20,7 +20,7 @@ func Test_OpenVPN_JSON(t *testing.T) {
 	data, err := json.Marshal(in)
 	require.NoError(t, err)
 	//nolint:lll
-	assert.Equal(t, `{"user":"","verbosity":0,"runAsRoot":true,"cipher":"","auth":"","provider":{"name":"name","serverSelection":{"networkProtocol":"","regions":null,"group":"","countries":null,"cities":null,"isps":null,"owned":false,"customPort":0,"numbers":null,"encryptionPreset":""},"extraConfig":{"encryptionPreset":"","openvpnIPv6":false},"portForwarding":{"enabled":false,"filepath":""}}}`, string(data))
+	assert.Equal(t, `{"user":"","verbosity":0,"runAsRoot":true,"cipher":"","auth":"","provider":{"name":"name","serverSelection":{"networkProtocol":"","regions":null,"group":"","countries":null,"cities":null,"hostnames":null,"isps":null,"owned":false,"customPort":0,"numbers":null,"encryptionPreset":""},"extraConfig":{"encryptionPreset":"","openvpnIPv6":false},"portForwarding":{"enabled":false,"filepath":""}}}`, string(data))
 	var out OpenVPN
 	err = json.Unmarshal(data, &out)
 	require.NoError(t, err)

internal/settings/providers.go

@@ -118,6 +118,14 @@ func GetWindscribeSettings(paramsReader params.Reader) (settings models.Provider
 	if err != nil {
 		return settings, err
 	}
+	settings.ServerSelection.Cities, err = paramsReader.GetWindscribeCities()
+	if err != nil {
+		return settings, err
+	}
+	settings.ServerSelection.Hostnames, err = paramsReader.GetWindscribeHostnames()
+	if err != nil {
+		return settings, err
+	}
 	settings.ServerSelection.CustomPort, err = paramsReader.GetWindscribePort(settings.ServerSelection.Protocol)
 	if err != nil {
 		return settings, err