This is a straightforward industrial electrical installation. There's a pad-mounted distribution transformer and meter provided by the power company, a weatherproof load center provided by the customer's electrical contractor, and the Tesla supercharger control unit and outlet stations. No big deal to install. There's a comparable installation at every large standalone store.
That's a small charging station. Here's the build-out of a bigger one. Black and Veach, which does infrastructure construction for the energy and communications industry (substations, cell sites, etc.) is doing the job. They see it as a lot like building out cell towers. (If you watch that video, you may wonder why the transformers and switchgear are on raised platforms. Probably because there's a flood risk at that location.)
Installing a gas station's underground tanks, which today are dual tanks with leak detection, is a much bigger job. There's a big excavation, lots of plumbing and wiring, and several different trades involved.