Came across this app called TV App Repo, been using on Shield TV (running latest android update) since last week and doing its job as it says. It really helps to bring shortcut to home screen for sideloaded apps. No more time spending to convert apps with utilities.

Playstore : https://play.google.com/store/apps/details?id=news.androidtv.tvapprepo.playstore

Playstore Description : Want to easily launch your non-Leanback apps from your homescreen? The Tv App Repo generates Leanback shortcuts and lets you install them. These tiny apps simply redirect you to the actual app.

The app is open source! Check it out on GitHub:

https://github.com/itvlab/tvapprepo/

Hope this helps.