rename file to fit revised page title

Author: TerryGLee

docs/install/import-export-configuration.md renamed to docs/install/import-export-installation-configurations.md

@@ -61,7 +61,7 @@
       - name: Update a network-based installation of Visual Studio
         href: install/update-a-network-installation-of-visual-studio.md
       - name: Import or export installation configurations
-        href: install/import-export-configuration.md
+        href: install/import-export-installation-configurations.md
       - name: Install and use Visual Studio behind a firewall or proxy server
         href: install/install-and-use-visual-studio-behind-a-firewall-or-proxy-server.md
         items: