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, 0 insertions, 16 deletions

diff --git a/docs/development/design/versioning.rst b/docs/development/design/versioning.rst
deleted file mode 100644
index 40e70f2..0000000
--- a/docs/development/design/versioning.rst
+++ /dev/null
@@ -1,16 +0,0 @@
-
-.. This work is licensed under a Creative Commons Attribution 4.0 International
-.. License.
-.. http://creativecommons.org/licenses/by/4.0
-.. (c) Cisco Systems, Inc
-
-Versioning
-==========
-
-NFVbench uses semver compatible git tags such as "1.0.0". These tags are also called project tags and applied at important commits on the master branch exclusively.
-Rules for the version numbers follow the semver 2.0 specification (https://semver.org).
-These git tags are applied indepently of the OPNFV release tags which are applied only on the stable release branches (e.g. "opnfv-5.0.0").
-
-In general it is recommeneded to always have a project git version tag associated to any OPNFV release tag content obtained from a sync from master.
-
-NFVbench Docker containers will be versioned based on the NFVbench project tags.