Signed-off-by: David Bauer <mail@david-bauer.net>

This was an idea (thought experiment?) from a Wireless Battlemesh ages
ago between batman-adv devs. Regarding what could be done to interconnect
isolated/separate WiFi mesh clouds on layer 3 without losing best path
metric information, without worsening/compromising on the best route decision.
And as a more sophisticated approach to the batman-adv gateway feature and
a potential replacement for tunneled batman-adv over VPN connections.

Which is the opposite of what the sentence in this Gluon README
is saying. And this never got implemented in either batman-adv nor Gluon.

Therefore removing this link to this old draft page.

The newly added information is way too verbose and non-practical for a
"Getting started". Therefore adding an "Overview" heading and moving the
"Getting started" back to where it originally was.

(cherry picked from commit b313a631)

Signed-off-by: David Bauer <mail@david-bauer.net>

Co-authored-by: David Bauer <mail@david-bauer.net>

(cherry picked from commit bf8c3bab)

Signed-off-by: David Bauer <mail@david-bauer.net>

(cherry picked from commit 7f3a3042)

(cherry picked from commit 447595f0)

(cherry picked from commit 63ebeb25)

(cherry picked from commit 239c379d)