Add the start of a rust program to switch options

- This program will be used to switch options, as well as to rebuild
  configuration
- Although it's in this git repo right now, it may not stay there in the long
  term (TBD)
diff --git a/switching/.gitignore b/switching/.gitignore
new file mode 100644
index 0000000..5895861
--- /dev/null
+++ b/switching/.gitignore
@@ -0,0 +1,2 @@
+target/
+.direnv/