check if directory creation was successfull

[naraesk]

In Settingsconfiguration.java we create directories using mkdirs(). We should check the return type and print an error message to the log, if the directory could not be created

Findbugs output:

Exceptional return value of java.io.File.mkdirs() ignored in org.getaviz.generator.SettingsConfiguration.loadConfig(String)

Exceptional return value of java.io.File.mkdirs() ignored in org.getaviz.generator.SettingsConfiguration.loadConfig(HttpServletRequest)