About page

[benlk]

Not simply expand the credits page: https://benlk.github.io/columbus-regional-rail/credits/

• [ ] ~fix footer link to not have double slash https://benlk.github.io/columbus-regional-rail//credits/~ 🤷
• [x] "is this real?"
• [x] "why?"
• [ ] "why not use this other platform?"
• [x] "who is this for?"
• [x] Link to roadmap: https://github.com/users/benlk/projects/3/views/1
• [x] link to Leaflet, slava ukraini 🇺‍🇦

[benlk]

• [x] split "Credits" and "About"