Add README to lib/ (#64)

Author: rachaelshaw

lib/README.md

@@ -0,0 +1,40 @@
+# `lib/`
+
+This folder is for files referenced by `path` in Fleet config YAML.
+
+This can reduce duplication for policies, scripts, and other config that is the same across multiple teams in Fleet Premium.
+
+### Examples
+
+##### Policies
+
+```yaml
+# default.yml
+policies:
+  - path: ./lib/macos-device-health.policies.yml
+```
+
+##### Queries
+
+```yaml
+# default.yml
+queries:
+  - path: ./lib/collect-usb-devices.queries.yml
+```
+
+##### Scripts
+
+```yaml
+# default.yml
+controls:
+  scripts:
+    - path: ./lib/remove-zoom-artifacts.script.sh
+```
+
+##### Agent options
+
+```yaml
+# default.yml
+agent_options:
+  path: ./lib/agent-options.yml
+```