Auto-generate sample config file

This PS auto-generates the sample config file using
oslo-config-generator which is how every project should reliably
produce a config file.

In addition, the Patrole documentation was updated to link to the
generated config file, so that the documentation accurately
shows config options.

Change-Id: Ib3c39084b4c2b5a0078d1293d882cf9a9050b29b
Closes-Bug: #1709490
7 files changed