Implement VAPython in pure Python

This PR uses betterproto to create a pure Python implementation for VAPython

docs/css/custom.css

+/* Indentation. */
+div.doc-contents:not(.first) {
+    padding-left: 25px;
+    border-left: .05rem solid var(--md-typeset-table-color);
+  }
\ No newline at end of file