.config: compile only YUN image

Signed-off-by: Federico Vaga <federicov@linino.org>
base-files: change names to 'arduino'

Signed-off-by: Federico Vaga <federicov@linino.org>
change default password to 'arduino'

Signed-off-by: Federico Vaga <federicov@linino.org>
webpanel-arduino: add webpanel for Arduino

This patch adds the arduino luci webpanel. In this patch I do not remove
the linino webpanel due to maintenability problems, but I just disable
it from the default configuration.

The master branch is the main branch of the linino distribution and it
uses the linino webpanel. In order to avoid git conflicts while rebasing
arduino branch I did not remove the linino webpanel.

Signed-off-by: Federico Vaga <federicov@linino.org>
webpanel-arduino: add dependency with luci admin

Signed-off-by: Federico Vaga <federicov@linino.org>
webpanel-arduino: replace index.html at first boot

Signed-off-by: Federico Vaga <federicov@linino.org>