Issues about the new website

[louisgreiner]

This PR proposes a new design for the website: #304

However, we've missed some critical issues during the review:

• the website is not responsive, especially using a smartphone
• some typos remain, giving an unfinished feeling of this site

Responsivness

• The site should be responsive, see Issues about the new website #335 (comment)

Typos

• Copyright line in i18n/* have a generic site name:
  • 🇫🇷 "Mon site web" -> "OSRD" (or "Open Source Railway Designer"?)
  • 🇬🇧 "My Website" -> "OSRD" (or "Open Source Railway Designer"?
• "a" is missing in content/_index.en.html:
  • 🇬🇧 "Open Source Railway Designer is free, open-source software" -> "Open Source Railway Designer is a free, open-source software"

Enhancements

If this is not time consuming, these enhancements would also be great:

• Update the "Join us" section:
  • Change the section name to "Contact"
  • 🇫🇷 "Pour en savoir plus ou si travailler sur OSRD vous intéresse, n'hésitez pas à nous contacter : contact@osrd.fr !"
  • 🇬🇧 "If you want to know more or if working on OSRD motivates you, feel free to contact us at contact@osrd.fr!"
• Being able to open a carrousel picture to enlarge it by clicking on the picture
• Add more space to the end of article footer (see screenshot)
  • The implementation might be padding-bottom: 10rem for the main element

Before	Expected

[emersion]

• Copyright line at the bottom says "My Website"

[celine-sncf]

The "Join us" section could also be reworked, in my opinion (especially as we don't recruit actively this year).
I would rename the section "Contact" and change the text as follows:

To know more about the project, feel free to contact us at [contact@osrd.fr](mailto:contact@osrd.fr)!

Pour en savoir plus sur le projet, n'hésitez pas à nous contacter : [contact@osrd.fr](mailto:contact@osrd.fr) !

[emersion]

This sounds orthogonal to the redesign TBH, and I'd rather leave the door open for an interesting resume to make its way into our inboxes.

[celine-sncf]

I think the original one is too restrictive, some people may want to contact us for other reasons that a job. Why don't we have both?

If you want to know more or if working on OSRD motivates you, feel free to contact us at [contact@osrd.fr](mailto:contact@osrd.fr)!

Pour en savoir plus ou si travailler sur OSRD vous intéresse, n'hésitez pas à nous contacter : [contact@osrd.fr](mailto:contact@osrd.fr) !

[thibautsailly]

Here is the layout adaptation for smaller screens. The first breakpoint is at 640px and the second one at 1080px.
https://sketch.com/s/4ec75e02-9373-4010-af4a-23ff77eaf75a/p/7B73B24F-0D56-4CE6-BD86-AB28C4A64ADE/canvas