make native logger and wry-panel logger bridged

[magic-cucumber]

1. make WryWebViewPanel.Companion public and modified 2 properties:
   • make LOG_ENABLED public and we can modifiy it's value.
   • add NATIVE_LOGGER property, and init the native logger in WryWebViewPanel.Companion.init。
2. add a property in WryWebViewPanel:

private val bridgeLogger: (String) -> Unit = { System.err.println(it) }

change the log() method:

    private fun log(message: String) {
        if (LOG_ENABLED) {
            bridgeLogger("[WryWebViewPanel] $message")
        }
    }