Add FHP Logo to Introduction

[seragarez]

[erictapen]

If you wonder how to add a logo: You can upload it into assets/ and then reference it with an img element, just like in https://github.com/erictapen/mapping-migration/blob/main/src/Introduction.elm#L44

[seragarez]

Do you know if Marian gave us "official" logo files to use? Can't find any on incom. Otherwise I could ask in our master's group, I'm sure someone has them.