pw_graphics: 32blit particle and text demo

Change-Id: I082395d0efd3da8d226a8270b96a696ff4f274d4
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/95500
Reviewed-by: Chris Mumford <cmumford@google.com>
Reviewed-by: Anthony DiGirolamo <tonymd@google.com>
Presubmit-Verified: CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com>
Commit-Queue: Anthony DiGirolamo <tonymd@google.com>
diff --git a/.gitmodules b/.gitmodules
index dcaa5dd..6c5f16c 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -26,3 +26,6 @@
 	path = infra/config
 	url = https://pigweed.googlesource.com/infra/config
 	branch = main
+[submodule "third_party/32blit/32blit-sdk"]
+	path = third_party/32blit/32blit-sdk
+	url = https://github.com/32blit/32blit-sdk