documentation : find duplicated infos between manual.grid.tf vs manual.threefold.io

[sasha-astiadi]

the new technical manual is up and running, it leaves some duplication on the old manual.threefold.io.

• [x] find the duplicated info and find a way how to present infos on both manuals that are active and running.

• [x] discuss the findings with documentation team and proceed to delete duplications

[sasha-astiadi]

closing this in favor of https://github.com/threefoldfoundation/info_manual3/issues/176