Improve honeynode installation process in tox

Improve honeynode installation process in tox

- update install_honeynode.sh script to allow an installation
  per version or a list of versions as argument(s)
  rather than forcing the installing of all versions systematically.
- remove honeynode installation from tox gnpy profile
  since gnpy test does not use any simulator.
- fix flexgrid placement in tox.ini (it should be with 2.2.1 profiles)
- split honeynode installation in 2 lines inside tox.ini
  so that the called profiles only install the honeynode version(s)
  that they need.
  This spares ressources and time on the gate and prevent
  the installation of version 7.1, which is currently not used.

JIRA: TRNSPRTPCE-368
Signed-off-by: guillaume.lambert <guillaume.lambert@orange.com>
Change-Id: Ic66c47a31b48ae5f04a9188222442729a76ee0c9