Implement New Winget Install Method (#1738)

- Removed Get-LatestHash from Install-WinUtilWinget.ps1, replaced by Get-WinUtilWingetLatest.ps1.
- Added new Winget Install method in case of choco failing to install. Environment refresh line included.
- Get-WinUtilWingetPrerequisites added: Downloads the prerequisites required for the latest version of Winget.
- Get-WinUtilWingetLatest added: Uses the GitHub API to find the latest version of Winget and download it along with the accompanied License1.xml file.

Fixes:
- Removed --scope=machine from winget install command in Install-WinUtilProgramWinget. Non-UWP Apps fail to install if scope is set to machine. Error code: 0x80070005. More information commented in file.

functions/private/Get-WinUtilWingetLatest.ps1

@@ -0,0 +1,23 @@
+function Get-WinUtilWingetLatest {
+    <#
+    .SYNOPSIS
+        Uses GitHub API to check for the latest release of Winget.
+    .DESCRIPTION
+        This function grabs the latest version of Winget and returns the download path to Install-WinUtilWinget for installation.
+    #>
+
+    Try{
+        # Grabs the latest release of Winget from the Github API for the install process.
+        $response = Invoke-RestMethod -Uri "https://api.github.com/repos/microsoft/Winget-cli/releases/latest" -Method Get -ErrorAction Stop
+        $latestVersion = $response.tag_name #Stores version number of latest release.
+        $licenseWingetUrl = $response.assets.browser_download_url[0] #Index value for License file.
+        Write-Host "Latest Version:`t$($latestVersion)`n"
+        $assetUrl = $response.assets.browser_download_url[2] #Index value for download URL.
+        Invoke-WebRequest -Uri $licenseWingetUrl -OutFile $ENV:TEMP\License1.xml
+        # The only pain is that the msixbundle for winget-cli is 246MB. In some situations this can take a bit, with slower connections.
+        Invoke-WebRequest -Uri $assetUrl -OutFile $ENV:TEMP\Microsoft.DesktopAppInstaller.msixbundle
+    }
+    Catch{
+        throw [WingetFailedInstall]::new('Failed to get latest Winget release and license')
+    }
+}