Clean up esbuilding of extensions

- Make sure we still always type check using `tsgo --noEmit`
- Align names of esbuild files
- Convert all esbuild files to typescript. We use the `.mts` extension to avoid annoying node warnings about using pacakges

extensions/markdown-math/tsconfig.browser.json

@@ -0,0 +1,9 @@
+{
+	"extends": "../tsconfig.json",
+	"compilerOptions": {
+		"types": [],
+		"typeRoots": [
+			"./node_modules/@types"
+		]
+	}
+}