Add frontmatter, markdown, path, xml, rss, and web packages

Sync local packages into the registry repo and update index.json
and README.md to include all 9 packages.

packages/markdown/lux.toml

@@ -0,0 +1,8 @@
+[project]
+name = "markdown"
+version = "0.1.0"
+description = "Markdown to HTML converter for Lux"
+authors = ["Brandon Lucas"]
+license = "MIT"
+
+[dependencies]