Fix: NoSuchFileException if configs\db\backup is not present on first start

[Ludy87]

Description

20:38:21.452 [restartedMain] ERROR s.s.S.c.s.database.DatabaseService - Error reading backup directory: configs\db\backup
java.nio.file.NoSuchFileException: configs\db\backup
        at java.base/sun.nio.fs.WindowsException.translateToIOException(WindowsException.java:85)
        at java.base/sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:103)
        at java.base/sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:108)
        at java.base/sun.nio.fs.WindowsDirectoryStream.<init>(WindowsDirectoryStream.java:86)
        at java.base/sun.nio.fs.WindowsFileSystemProvider.newDirectoryStream(WindowsFileSystemProvider.java:541)
        at java.base/java.nio.file.Files.newDirectoryStream(Files.java:613)
        at stirling.software.SPDF.config.security.database.DatabaseService.getBackupList(DatabaseService.java:80)
        at stirling.software.SPDF.config.security.database.DatabaseService.exportDatabase(DatabaseService.java:156)
        at stirling.software.SPDF.config.security.UserService.saveUser(UserService.java:214)
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
        at java.base/java.lang.reflect.Method.invoke(Method.java:580)
        at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:359)
        at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:723)
        at stirling.software.SPDF.config.security.UserService$$SpringCGLIB$$3.saveUser(<generated>)
        at stirling.software.SPDF.config.security.InitialSecuritySetup.createDefaultAdminUser(InitialSecuritySetup.java:76)
        at stirling.software.SPDF.config.security.InitialSecuritySetup.initializeAdminUser(InitialSecuritySetup.java:67)
        at stirling.software.SPDF.config.security.InitialSecuritySetup.init(InitialSecuritySetup.java:42)
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
        at java.base/java.lang.reflect.Method.invoke(Method.java:580)
        at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMethod.invoke(InitDestroyAnnotationBeanPostProcessor.java:457)
        at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMetadata.invokeInitMethods(InitDestroyAnnotationBeanPostProcessor.java:401)
        at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:219)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:423)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1800)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:601)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:523)
        at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:336)
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:289)
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:334)
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.instantiateSingleton(DefaultListableBeanFactory.java:1122)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingleton(DefaultListableBeanFactory.java:1093)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:1030)
        at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:987)
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:627)
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:146)
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:752)
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:439)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:318)
        at stirling.software.SPDF.SPDFApplication.main(SPDFApplication.java:117)
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
        at java.base/java.lang.reflect.Method.invoke(Method.java:580)
        at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:50)

Checklist

• I have read the Contribution Guidelines
• I have performed a self-review of my own code
• I have attached images of the change if it is UI based
• I have commented my code, particularly in hard-to-understand areas
• If my code has heavily changed functionality I have updated relevant docs on Stirling-PDFs doc repo
• My changes generate no new warnings
• I have read the section Add New Translation Tags (for new translation tags only)