Add funding agency logos and update acknowledgements

[sloede]

Issue for logo storage: #1390

[jlchan]

@sloede the logos don't all fit on one line - do you mind if I change the widths?

[sloede]

@sloede the logos don't all fit on one line - do you mind if I change the widths?

Not at all. However, instead of making them all the same width, could you try making them approximately the same size in the eyeball norm? Right now, the NSF Logo is massive (since it has only large letters and nearly no white space in the margins), while the DFG and ERC logos already feel "cramped".

If it turns out that the logos do not look good anymore on a single line, we can also consider to deliberately put them on two lines.

[jlchan]

Modified the formatting a little more and tried a new NSF logo. I think that helps the NSF logo, but now the Swedish Research Council looks a little odd now compared to the rest.

[sloede]

The acknowledgments section now looks like this:

Documenter.jl does not allow HTML formatting, so it is no easy feat to put the logos there such that it looks nice - if someone wants to give it a try, please go ahead; for now I just synchronized the texts.

[jlchan]

Looks great!

[andrewwinters5000]

Looks great, thanks for taking care of this @sloede!