These PvP-themed decorations are available to all players, they just cost quite a few credits. To buy them, you need to travel to the Strongholds and Crew Skills section of the fleet and purchase as many copies as you want with credits from the Starfighter & PvP Decoration Vendor. These decorations range from 200 Credits to 250,000 Credits, so some are very cheap and some are more expensive. These decorations used to cost a type of currency called “Warzone Commendations”, but since those no longer exist, they now just cost credits. These decorations are unrelated to the PvP Seasons decorations.
The Makeb Pergola decoration can be bought for 25,000 credits. It can be bought from a vendor in a room with a guild bank in the Crafting & Strongholds section of the fleet, NOT in the PvP section of the fleet. It does not require any special skills or PvP to acquire, just credits.
This item can be bought and sold on the GTN - beware of scammers and don't buy it from the GTN unless it is less than 25,000 Credits.