Update rally-jobs files

* Rename rally-scenarios directory to rally-jobs. Because actually
  this directory contains files related to job and not scenarios.

* Upadte main README file

* Add readme files to rally-jobs/extra and rally-jobs/plugins

Change-Id: I111c3c3f86ab4886d3a7b66c7bf7c050c1d9ca1a

rally-jobs/README.rst

@@ -0,0 +1,30 @@
+Rally job related files
+=======================
+
+This directory contains rally tasks and plugins that are run by OpenStack CI.
+
+Structure
+---------
+
+* plugins - directory where you can add rally plugins. Almost everything in
+  Rally is a plugin. Benchmark context, Benchmark scenario, SLA checks, Generic
+  cleanup resources, ....
+
+* extra - all files from this directory will be copy pasted to gates, so you
+  are able to use absolute paths in rally tasks.
+  Files will be located in ~/.rally/extra/*
+
+* glance.yaml is a task that is run in gates against OpenStack (nova network)
+  deployed by DevStack
+
+
+Useful links
+------------
+
+* More about Rally: https://rally.readthedocs.org/en/latest/
+
+* How to add rally-gates: https://rally.readthedocs.org/en/latest/rally_gatejob.html
+
+* About plugins:  https://rally.readthedocs.org/en/latest/plugins.html
+
+* Plugin samples: https://github.com/stackforge/rally/tree/master/doc/samples/plugins

rally-jobs/extra/README.rst

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+Extra files
+===========
+
+All files from this directory will be copy pasted to gates, so you are able to
+use absolute path in rally tasks. Files will be in ~/.rally/extra/*

rally-jobs/plugins/README.rst

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+Rally plugins
+=============
+
+All *.py modules from this directory will be auto-loaded by Rally and all
+plugins will be discoverable. There is no need of any extra configuration
+and there is no difference between writing them here and in rally code base.
+
+Note that it is better to push all interesting and useful benchmarks to Rally
+code base, this simplifies administration for Operators.

rally-scenarios/README.rst

@@ -1,13 +0,0 @@
-This directory contains rally benchmark scenarios to be run by OpenStack CI.
-
-Structure:
-* glance.yaml is rally task that will be run in gates
-* plugins - directory where you can add rally plugins. So you don't need
-  to merge benchmark in scenarios in rally to be able to run them in glance.
-* extra - all files from this directory will be copy pasted to gets, so you
-  are able to use absolute path in rally tasks. Files will be in ~/.rally/extra/*
-
-
-* more about rally: https://wiki.openstack.org/wiki/Rally
-* how to add rally-gates: https://wiki.openstack.org/wiki/Rally/RallyGates
-* how to write plugins https://rally.readthedocs.org/en/latest/plugins.html