For the next time, I've now written a small powershell script to automate this. It works by starting the launcher, waiting a couple of minutes and killing it's process. This only works if you turn off the bulk download in the launcher, which will slow your download! Also, while the script should only kill processes which are named "Launcher.exe" and have the title "Warframe", killing processes can fuck up your computer, so be aware of this if you decide to use this.

So, now we got that out of the way, the quick tutorial:

Open up a text editor and paste the following text into it:

while($true){ #infinite loop
    $p = Get-Process -Name Launcher |Where {$_.MainWindowTitle.Contains("Warframe")}   #Get all process objects which are called "Launcher" and have "Warframe" as their title
    if(!$p) # if this process does not exist ...
    {
        Start-Process steam://rungameid/230410 #run Warframe via Steam
    }
    Start-Sleep 1800 #wait 15 minutes
    Get-Process -name Launcher | Where {$_.MainWindowTitle.Contains("Warframe")} | Stop-Process -whatif #kill all processes which are called "Launcher" and have "Warframe" as their title
}

The text after the hash keys explains what the line does and has no influence on the script itself.
Save the file as "WarframeAutoPatcher.ps1". Right click it, there should be an entry in your context menu to execute it via powershell. Do that and wait ~