Bottle tree lighting
It sounds like the issue isn't 12 VDC vs 12 VAC, but rather, wanting to run your bottle-tree lighting on mains voltage of 120 VAC or 230 VAC. Mains voltage will kill you. 

As such, your nation will have an Electrical Code which describes proper wiring methods for wiring with mains voltage.  It's possible to get power there, but you have to follow the rules.  If you don't, and someone gets hurt, expect to lose freedom, fortune or both. 

I know, right?  For EE's and electronic hobbyists, wiring methods are the last thing you ever think of.  It is the crux of electrician-type electrical work.  Playing fast-and-loose with wiring is fine for low-voltage lighting, which is why everyone's been frame-shifting you into it, as do I.  Outdoor "transformers"/power supplies are readily available, as LV lighting is widely used in outdoor garden, pool and path lighting for exactly this reason. 

But if you really, really want to wire it 120/230V, grab that Electrical Code (or possibly your jurisdiction's appliance wiring standards, UL standards are generally accepted the world over) and build your fixture to code.  Hobbyists do it all the time, just usually they're building chandeliers that will be living indoors so they don't have to follow the "wet location" rules. 

Honestly it seems like mains-voltage lighting would be too bright. (theorists: this is a procurement issue.)  By which I mean, you're trying to accent/highlight the bottles, not overwhelm them, and my hunch is you'll want a certain luminosity. IMO that'll be rather easy to buy in low-voltage, and it will be a struggle to source in mains voltage at sane cost, that is reliable.