[examples/data-literate][m]: factor our a working markdown+CSV (data literate) example from site (where we already had a demo).

* removed a few extraneous things
* added the README.md with some instructions

examples/data-literate/README.md

@@ -0,0 +1,57 @@
+This example renders markdown + CSV into an elegant web page. These type of data setup we term [data literate][]
+
+[data literate]: https://portaljs.org/data-literate
+
+## How to use
+
+```bash
+npx create-next-app -e https://github.com/datopian/portal.js/tree/main/examples/data-literate
+# choose a name for your portal when prompted e.g. your-portal or go with default my-app
+
+# then run it
+cd your-portal
+yarn #install packages
+yarn dev # start app in dev mode
+```
+
+You should see the demo portal running with the example dataset provided:
+
+TODO
+
+### Use your own dataset
+
+You can try it out with your own data literate setups:
+
+In the directory of your portal do:
+
+```bash
+export PORTAL_DATASET_PATH=/path/to/my/dataset
+```
+
+Then restart the dev server:
+
+```
+yarn dev
+```
+
+Check the portal page and it should have updated e.g. like:
+
+TODO
+
+### Static Export
+
+Build the export:
+
+```
+yarn build
+```
+
+Results will be in `out/` subfolder.
+
+To test you will need to run a local webserver in the folder (just opening the relevant file in your browser won't work):
+
+```
+cd out
+python3 -m http.server
+```
+