Populate and polish website

[emdupre]

The current website has initial populated content, but it could use a few updates :

• The individual talks for last year's speakers should all be linked out from the Nilearn Events Youtube channel
• The sprint infrastructure content should be added as it is decided
• The wording should be adjusted throughout, particularly on the main page re: the motivation for this year's dev days !

[NicolasGensollen]

Not sure this is what you had in mind, but I added the links to the youtube videos for the last year talks (see 4ba3839)

[bthirion]

Thx!

[emdupre]

Thanks, @NicolasGensollen ! I went ahead and removed the scheduling information for last year's talks in 4868687. I had added this year's in fcdc8c7, and I imagine we don't need both :)

[emdupre]

@bthirion should we adjust the wording through to highlight Nibabel as well ?

[bthirion]

Indeed. @NicolasGensollen can you do at least a pass on that before we start to communicate ?
Thx,

[NicolasGensollen]

I changed the wording, and added a few pointers to Nibabel resources in 406eb73.
I'm not sure at what point we want to integrate Nibabel here though... I changed the page title, but not the logo for example. Feel free to undo some changes if needed.