Remove (outdated) zap-baseline.py script

Remove zap-baseline.py script, it's not being maintained in this repo.
Add README to examples directory and link to the (maintained)
zap-baseline.py script.

Author: thc202

src/examples/README.md

@@ -0,0 +1,9 @@
+# Examples
+
+This directory contains example Python scripts using the OWASP ZAP Python API.
+
+## Other Scripts
+
+Other Python scripts, not contained in this repository, that use the OWASP ZAP Python API:
+
+ - [zap-baseline.py](https://github.com/zaproxy/zaproxy/blob/develop/build/docker/zap-baseline.py), for more information about the script refer to the [ZAP Baseline Scan](https://github.com/zaproxy/zaproxy/wiki/ZAP-Baseline-Scan) wiki page.