chore: remove .devcontainer from the repo and gitignore it

Keep devcontainer setups local to each developer instead of tracked in
the repository.

Signed-off-by: Date Huang <tjjh89017@hotmail.com>

Author: tjjh89017

.devcontainer/devcontainer.json

@@ -32,3 +32,4 @@ go.work.sum
 .vscode/
 
 bin/
+.devcontainer/