Making cannabis butter — with CBD, THC or both — is not rocket science, but it’s also not a walk in the park. That became clear during one of the twice-a-month cooking classes offered at Market Street Wellness in Medford. There’s a fair amount of important information you want to master, starting with the need to decarboxylate your green matter. Now, don’t let that five-syllable word scare you off. It just means you have to…