Refresh architecture diagram with ONNX and LiteRT inputs. (iree-org#19494)

Progress on iree-org#18174.

I suggest the rich diff "swipe" view to see what changed. Updates in
text form:

* Added ONNX to input frameworks in the top left and swapped "TOSA" for
"LiteRT".
* Reordered the input frameworks (roughly ordered by momentum and
grouped TF with LiteRT, but could also sort alphabetically).
* Exporting somehow changed the font to from [Virgil, Cascadia,
Assistant] sourced from e.g. `https://excalidraw.com/Cascadia.woff2` to
just Cascadia, sourced from an inlined base64-encoded blob (so +1.87KB
file size). I don't mind the changes.
* Removed _extremely_ small "Stacked Column" text from the "Profiling
Feedback" chart on the right that looked like an artifact of the diagram
generation.

Author: ScottTodd

docs/website/docs/assets/images/.gitignore

@@ -0,0 +1,2 @@
+# Commit as iree_architecture.excalidraw.gz instead (~10x compression ratio).
+iree_architecture.excalidraw