Improve performance of Package identification

Using -ListAvailable with Get-Command to ensure no module loading is
    attampeted while querying loaded commands.
    This improved performance when certain modules have not been
    loaded yet

base.linux/profile.d/UnixCompleters.ps1

@@ -1,4 +1,4 @@
-Get-Command Import-UnixCompleters -ErrorAction SilentlyContinue | ForEach-Object {
+Get-Command -ListImported Import-UnixCompleters -ErrorAction SilentlyContinue | ForEach-Object {
   Import-UnixCompleters
   Set-UnixCompleter -ShellType Bash
 }