adding common scripts for use by multiple dev scenario scripts (#59)

This PR gets Master up to date with the common scripts approach.  These are not done but this seems far enough along to proceed.  We'll now move forward with refining these common scripts along with the dev scenario scripts that reference them.

dev_ml_python.ps1

@@ -4,43 +4,27 @@
 
 Disable-UAC
 
-#--- Windows Features ---
-Set-WindowsExplorerOptions -EnableShowHiddenFilesFoldersDrives -EnableShowProtectedOSFiles -EnableShowFileExtensions
+# see if we can't get calling URL somehow, that would eliminate this need
+# should move to a config file
+$user = "Microsoft";
+$baseBranch = "BreakUpScripts";
+$finalBaseHelperUri = "https://raw.githubusercontent.com/$user/windows-dev-box-setup-scripts/$baseBranch/scripts";
 
-#--- File Explorer Settings ---
-Set-ItemProperty -Path HKCU:\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced -Name NavPaneExpandToCurrentFolder -Value 1
-Set-ItemProperty -Path HKCU:\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced -Name NavPaneShowAllFolders -Value 1
-Set-ItemProperty -Path HKCU:\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced -Name LaunchTo -Value 1
-Set-ItemProperty -Path HKCU:\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced -Name MMTaskbarMode -Value 2
+function executeScript {
+    Param ([string]$script)
+    write-host "executing $finalBaseHelperUri/$script ..."
+	iex ((new-object net.webclient).DownloadString("$finalBaseHelperUri/$script"))
+}
 
-#--- Git ---
-choco install -y git -params '"/GitAndUnixToolsOnPath /WindowsTerminal"'
-
-#--- Windows Subsystems/Features ---
-choco install -y Microsoft-Hyper-V-All -source windowsFeatures
-choco install -y Microsoft-Windows-Subsystem-Linux -source windowsfeatures
-
-#--- Ubuntu ---
-# Invoke-WebRequest -Uri https://aka.ms/wsl-ubuntu-1604 -OutFile ~/Ubuntu.appx -UseBasicParsing
-# Add-AppxPackage -Path ~/Ubuntu.appx
-
-#--- Fonts ---
-choco install -y inconsolata
-# choco install -y ubuntu.font
-
-#--- Tools ---
-choco install -y docker-for-windows
-choco install -y python
-choco install -y 7zip.install
+#--- Setting up Windows ---
+executeScript "SystemConfiguration.ps1";
+executeScript "FileExplorerSettings.ps1";
+executeScript "RemoveDefaultApps.ps1";
+executeScript "CommonDevTools.ps1";
+executeScript "VirtualizationTools.ps1";
 
 # TODO: install additional ML tools
 
-#--- VS Code ---
-choco install -y vscode
-
-#--- VS Code extensions ---
-choco install -y vscode-docker
-
 Enable-UAC
 Enable-MicrosoftUpdate
 Install-WindowsUpdate -acceptEula