[Dev Container] - Adding VSCode Dev Container Capability (#12921)

This PR aims to add support for VS Code development container -
https://github.com/openxla/iree/issues/12907

Full Documentation: .devcontainer/README.md

---------

Co-authored-by: Scott Todd <scotttodd@google.com>
Co-authored-by: Geoffrey Martin-Noble <gcmn@google.com>
diff --git a/.gitignore b/.gitignore
index d2056f0..569d140 100644
--- a/.gitignore
+++ b/.gitignore
@@ -72,5 +72,8 @@
 *.tar
 *.tar.*
 
+# VS Code DevContainer
+.devcontainer/docker-compose.yml
+
 # Local cache files
 llvm-external-projects/iree-dialects/.cache