Complete redo of content indexing and querying (#517)

Complete redo of data store
Introduces live queries and live templates

common/syscalls/markdown.ts

@@ -0,0 +1,12 @@
+import { SysCallMapping } from "../../plugos/system.ts";
+import { parse } from "../markdown_parser/parse_tree.ts";
+import { Language } from "../../web/deps.ts";
+import type { ParseTree } from "$sb/lib/tree.ts";
+
+export function markdownSyscalls(lang: Language): SysCallMapping {
+  return {
+    "markdown.parseMarkdown": (_ctx, text: string): ParseTree => {
+      return parse(lang, text);
+    },
+  };
+}