feat: add views and styles for rendering html

src/views/layout.pug

@@ -0,0 +1,13 @@
+block variables
+doctype html
+html
+  head
+    meta(charset="utf-8")
+    meta(name="viewport", content="width=device-width, initial-scale=1, shrink-to-fit=no")
+    meta(name="theme-color", content="#000000")
+    link(rel="shortcut icon", href="/favicon.ico")
+    link(rel="stylesheet" href="/styles.css")
+    title SASJS Executor
+  body
+    div#root
+      block layout-content