docs: refresh & structure overhaul

Rework the doc in order to improve the navigation experience and to make
it easier to update the doc:

- simplify structure: docs/{release-notes,user,developer}
- recreate sphinx config file
- switch theme from opnfv to piccolo
- fix minor rst issues
- fix external references
- add missing license headers (add a short header with copyright and
  SPDX license identifier to the files lacking the information.  The
  header is based on https://github.com/david-a-wheeler/spdx-tutorial)

Change-Id: I9a1135a2873d9955beb26760e0cb6c5d6c1326bd
Signed-off-by: Gwenael Lambrouin <gwenael.lambrouin@orange.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/docs/developer/design/index.rst b/docs/developer/design/index.rst
new file mode 100644
index 0000000..4c52f98
--- /dev/null
+++ b/docs/developer/design/index.rst
@@ -0,0 +1,17 @@
+.. This work is licensed under a Creative Commons Attribution 4.0 International
+.. License.
+.. http://creativecommons.org/licenses/by/4.0
+.. (c) Cisco Systems, Inc
+
+=====================
+NFVbench Design Notes
+=====================
+
+.. toctree::
+   :maxdepth: 2
+
+   overview
+   design
+   versioning
+   traffic_desc
+   ndrpdr