No xeno slavery option?

[GAGA Extrem]

Egalitarian Xenophobes can enslave other species just fine.

Just remember that this is done on species level now, so you have to go to the species tab, select the target species and then open the SET RIGHTS subtab.
This is also the place where you can enable migration controls.

 

[GAGA Extrem]

Right, it looks like the recent change for this didn't make it into release.

I'll add a quick fix for you until it's officially patched (works fine on my beta build).
Copy the attached file to your Stellaris\common\policies folder and overwrite the existing one.