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, 8 insertions, 4 deletions

diff --git a/docs/index.rst b/docs/index.rst
index 720b670..1339a7f 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -3,9 +3,13 @@
 .. http://creativecommons.org/licenses/by/4.0
 .. (c) Cisco Systems, Inc
 
+
+NFVbench |release| Documentation
+================================
+
 .. toctree::
-   :maxdepth: 1
+   :maxdepth: 2
 
-   development/index
-   release/release-notes/index
-   testing/index
+   release-notes/index
+   user/index
+   developer/index