[JENKINS-47324] - Reduce usage of File.mkdirs() in FilePath and IOUtils (#3173)

* Move an instance of renameTo() to Files.move()

* Replace an instance of File.toURI() with an instance of Path.toUri()

* Replace mkdirs() with Files.createDirectories()
Replace mkdir() with Files.createTempDirectory()

* Undo addition of createTempDirectory() as per review comments

* Return to use of FilePath#mkdirs(File) and instead modify it to use the new API.

* Undo addition of toPath() in a URI conversion as it brings no benefits.

* Replace new uses of toPath() with Util.fileToPath() to pre-handle runtime exceptions

* Remove * import.
move mkdirs() to using FilePath method instead of File method.

* Make IOUtils.mkdirs(File) use Java7 API calls

* Add back accidentally removed imports.

* Fixed use of wildcard import

* Use utility method fileToPath() to handle potential exception thrown