Add uninstall to the chocolatey package

refs #11369

icinga2.nuspec

@@ -22,5 +22,6 @@
   </metadata>
   <files>
     <file src="tools\chocolateyInstall.ps1" target="tools" />
+    <file src="tools\chocolateyUninstall.ps1" target="tools" />
   </files>
 </package>

tools/chocolateyUninstall.ps1

@@ -0,0 +1,25 @@
+$instDir = "unset"
+$uninstaller = "Uninstall.exe"
+$icingaRegistry64bitOS = "hklm:\SOFTWARE\Wow6432Node\Icinga Development Team\ICINGA2"
+$icingaRegistry32bitOS = "hklm:\SOFTWARE\Icinga Development Team\ICINGA2"
+$found = $false
+$validExitCodes = @(0)
+
+if(test-path $icingaRegistry32bitOS) {
+  $instDir = (get-itemproperty -literalpath $icingaRegistry32bitOS).'(default)'
+  $found = $true
+}
+elseif(test-path $icingaRegistry64bitOS) {
+  $instDir = (get-itemproperty -literalpath $icingaRegistry64bitOS).'(default)'
+  $found = $true
+}
+else {
+  Write-Host "Did not find a path in the registry to the Icinga2 folder, did you use the installer?"
+} 
+
+if ($found) {
+  $packageArgs = "/S ?_="
+  $statements = "& `"$instDir\$uninstaller`" $packageArgs`"$instDir`""
+
+  Start-ChocolateyProcessAsAdmin "$statements" -minimized -validExitCodes $validExitCodes
+}