Update Windows icon and NSIS banner (JuliaLang#32054)

Author: musm

contrib/windows/7zS.sfx

@@ -1,4 +1,4 @@
 ;!@Install@!UTF-8!
-Title="The Julia Language"
+Title="Julia"
 RunProgram="julia-installer.exe"
 ;!@InstallEnd@!

contrib/windows/7zSFX-config.txt

@@ -9,6 +9,7 @@ SetCompress off
 CRCCheck off
 SetDataBlockOptimize on
 ShowInstDetails nevershow
+ShowUninstDetails nevershow
 RequestExecutionLevel user
 BrandingText " "
 
@@ -29,6 +30,9 @@ Caption "Julia Installer" # title bar
 !define MUI_ICON "${JULIAHOME}\contrib\windows\julia.ico"
 !define MUI_UNICON "${JULIAHOME}\contrib\windows\julia.ico"
 !define MUI_WELCOMEFINISHPAGE_BITMAP "${JULIAHOME}\contrib\windows\julia-banner.bmp"
+!define MUI_HEADERIMAGE
+!define MUI_HEADERIMAGE_BITMAP "${JULIAHOME}\contrib\windows\julia-header.bmp"
+!define MUI_HEADERIMAGE_RIGHT
 
 # Uninstall settings
 !define UninstLog "uninstall.log"