Feature: filter Surfshark servers by hostname

internal/configuration/surfshark.go

@@ -9,6 +9,10 @@ func (settings *Provider) surfsharkLines() (lines []string) {
 		lines = append(lines, lastIndent+"Regions: "+commaJoin(settings.ServerSelection.Regions))
 	}
 
+	if len(settings.ServerSelection.Hostnames) > 0 {
+		lines = append(lines, lastIndent+"Hostnames: "+commaJoin(settings.ServerSelection.Hostnames))
+	}
+
 	return lines
 }
 
@@ -30,5 +34,10 @@ func (settings *Provider) readSurfshark(r reader) (err error) {
 		return err
 	}
 
+	settings.ServerSelection.Hostnames, err = r.env.CSVInside("SERVER_HOSTNAME", constants.SurfsharkHostnameChoices())
+	if err != nil {
+		return err
+	}
+
 	return nil
 }