Feats : Adds SDIS 07 in partners

[fe51]

I would have liked to include the SDIS 07 in our partners as they have supported us since the beginning of the project.

Hence the PR introduces the following modifications :

• added a third sponsor, SDIS Ardèche
• added its desc, english and french
• updates Atraksis desc accordingly, en and fr

Below the screenshots to see how it renders

• French
• English

Happy to discuss it !

[fe51]

Thanks for the review ! Suggestions taken into account @frgfm :)