TRestTools::DownloadRemoteFile now checks if the file exists locally, and skips downloading if it is the case

[jgalan]

• TRestTools::DownloadRemoteFile will now check first if the file was previously downloaded. A force flag had been added to the method in case we need to force the download and overwrite the local file, however, the default is force=0.

Major change happens at commit 2947338 and 07941fd

Other changes are related with refactoring using clang-format script.