Add File.java to forbidden APIs

This commit cuts over all of core (not quite all tests) to java.nio.Path
It also adds the file class to the core forbidden APIs to prevent its usage
May be a try with resources here?

```java
try (InputStream is = Files.newInputStream(pluginPropFile)) {
    pluginProps.load(is);
    description = pluginProps.getProperty("description", PluginInfo.DESCRIPTION_NOT_AVAILABLE);
    version = pluginProps.getProperty("version", PluginInfo.VERSION_NOT_AVAILABLE);
} catch (Exception e) {
    // Can not load properties for this site plugin. Ignoring.
    logger.debug("can not load {} file.", e, esPluginPropertiesFile);
}
```