Add feature_request mechanism

This will be standart way for end users to ask Rally team to get
some new feature.

The idea is to make it realy simple for end users to ask about covering
their use cases.

E.g. to add request users don't need to deep dive in rally community,
road map and how it works. They need just to share their use cases
that is not covered by current rally functionality.

As a bonus adding some Readme.rst files related to doc/* dirs

Change-Id: I4c615101012ac9d1668ed766ac831f7e5c8129a8
Mention 'rally info' command in docs

Add description of 'rally info' to the corresponding part of docs/source/usage.rst.

Also remove a sentence with a non-existing link to the benchmark scenario
descriptions & usage page.

Change-Id: If9ee8de3e2dec1dd2784317f5da245744c5e7981
Merge "Add feature_request mechanism"
Trying to ingore races related to Nova + restoring missing benchmark

Seems like Nova has some fix related to checking default security group
to avoid it we can add more tenants in 2 benchmarks that are failing
boot_and_bounce_server and boot_and_resize

Restore nova-boot with nics

Change-Id: If625910a581afba0224e4ac591373d132d7f8efd
Merge "Mention 'rally info' command in docs"
Merge "Trying to ingore races related to Nova + restoring missing benchmark"
Fix rps._worker_process

  Fixed potential ZeroDivision places.
  Added unit test for real rps calculations.

  Closes-Bug: #1361460

Change-Id: I656d0a2e6712283bc3b220ec2df5b8737868a96c