Set useful Sumatra PDF Viewer default settings. This will only work on windows.
Existing files are renamed ("_old_n" appended), not overwritten.
At the given path with "SumatraPDF.exe", it creates "sumatrapdfrestrict.ini" with SavePreferences = 1 and FullscreenAccess = 1.
At the given roampath, it creates "SumatraPDF-settings.txt" with ShowToc = false and DefaultDisplayMode = single page.
UiLanguage gets filled in by Sumatra itself upon first opening.