(chocolatey#3327) Improves UX of Chocolatey Install without 4.8

This commit introduces the idea that the dotnet installation needing a reboot should not immediately halt the Chocolatey installation, but instead proceed as far as possible - then prompt for a reboot.

nuspec/chocolatey/chocolatey/tools/chocolateysetup.psm1

@@ -126,7 +126,7 @@ function Initialize-Chocolatey {
     $installModule = Join-Path $thisScriptFolder 'chocolateyInstall\helpers\chocolateyInstaller.psm1'
     Import-Module $installModule -Force
 
-  Install-DotNet48IfMissing
+    Install-DotNet48IfMissing
 
     if ($chocolateyPath -eq '') {
         $programData = [Environment]::GetFolderPath("CommonApplicationData")
@@ -204,13 +204,20 @@ Creating Chocolatey folders if they do not already exist.
         $env:ChocolateyExitCode = 0
     }
 
-    @"
+    if ($script:DotNetInstallRequiredReboot) {
+        @"
+Chocolatey (choco.exe) is nearly ready.
+You need to restart this machine prior to using choco.
+"@ | Write-Output
+    } else {
+        @"
 Chocolatey (choco.exe) is now ready.
 You can call choco from anywhere, command line or powershell by typing choco.
 Run choco /? for a list of functions.
 You may need to shut down and restart powershell and/or consoles
  first prior to using choco.
 "@ | Write-Output
+    }
 
     if (-not $allowInsecureRootInstall) {
         Remove-OldChocolateyInstall $defaultChocolateyPathOld
@@ -812,7 +819,8 @@ function Install-DotNet48IfMissing {
         $s = [System.Diagnostics.Process]::Start($psi);
         $s.WaitForExit();
         if ($s.ExitCode -eq 1641 -or $s.ExitCode -eq 3010) {
-          throw ".NET Framework 4.8 was installed, but a reboot is required. `n Please reboot the system and try to install/upgrade Chocolatey again."
+          Write-Warning ".NET Framework 4.8 was installed, but a reboot is required before using Chocolatey."
+          $script:DotNetInstallRequiredReboot = $true
         }
         if ($s.ExitCode -ne 0) {
             if ($netFx48InstallTries -ge 2) {
@@ -832,11 +840,11 @@ function Invoke-Chocolatey-Initial {
     try {
         $chocoInstallationFolder = Get-ChocolateyInstallFolder
         $chocoExe = Join-Path -Path $chocoInstallationFolder -ChildPath "choco.exe"
-        & $chocoExe -v | Out-Null
+        $runResult = & $chocoExe -v
         Write-Debug "Chocolatey execution completed successfully."
     }
     catch {
-        Write-ChocolateyWarning "Unable to run Chocolatey at this time.  It is likely that .Net Framework installation requires a system reboot"
+        Write-ChocolateyWarning "Unable to run Chocolatey at this time:`n$($runResult)"
     }
 }