Resolve foodcritic findings

```
FC011: Missing README in markdown format: ./README.md:1
FC024: Consider adding platform equivalents: ./recipes/default.rb:35
FC024: Consider adding platform equivalents: ./recipes/stanchion.rb:36
FC043: Prefer new notification syntax: ./recipes/default.rb:96
FC043: Prefer new notification syntax: ./recipes/stanchion.rb:101
FC045: Consider setting cookbook name in metadata: ./metadata.rb:1
```

For FC043, I opted to move the notifications to `notifies` on the file resources, as using the newer notification syntax for multiple resources (in this case the two files) requires multiple notification lines:

```
service "pacman" do
  subscribes :restart, "file[cherry]"
  subscribes :restart, "file[banana]"
end
```