They've been removed from the game, so you can't use them anymore. Shadowbringers changed how the tanks work, yes. It's simplified, and you have all of your major tools before you enter the first dungeon.
- The DPS stance was removed, and now you just have the tank stance. You'll turn Shield Oath on if you're tanking, and turn it off if you're not. With it on, you'll generate so much aggro that you won't even think about it anymore.
-- Sword Oath still does exist, but it's more or less just a consumable buff you get at level 76 to use for Atonement.
- Flash was replaced with Total Eclipse, and it really serves the same purpose. You do get a proper combo action with it, Prominence, at level 40, though.
Here you go.