Add stylelint and configure eslint to add custom plugin.

- Split up main.ts into multiple files.

esbuild.config.mjs

@@ -15,7 +15,7 @@ const context = await esbuild.context({
 	banner: {
 		js: banner,
 	},
-	entryPoints: ["main.ts"],
+	entryPoints: ["src/main.ts"],
 	bundle: true,
 	external: [
 		"obsidian",
@@ -45,4 +45,4 @@ if (prod) {
 	process.exit(0);
 } else {
 	await context.watch();
-}
+}