In this commit, we:
- move the sponsors of the Buildroot Meeting at ELCE 2018 to "Past
Sponsors"
- move Scaleway, as a sponsor of Hackathon in Paris in 2018 to "Past
Sponsors"
- merge the Free Electrons and Bootlin entries together in "Past
Sponsors"
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>