Fix footer styling. Addresses #1777

[vnbaaij]

Footer styling comes with a bad design decission made in the past. It uses a display: grid; together with flex-direction: column; which does not make any sense.

We are even overriding it in the demo site ourselves:

With this change we will change it to more sane defaults. Technically it might be considered a breaking change (albeit a small one for sure) but it be will changed in the next release to:

.footer {
    display: flex;
    z-index: 10;
    flex-direction: row;
    font-family: var(--body-font);
    font-weight: normal;
    font-size: var(--type-ramp-minus-1-font-size);
    line-height: var(--type-ramp-minus-1-line-height);
}

For the templates this means that a FluentSpacer is added to the footer so the texts will still align left an right. It also allows to remove some then redundant CSS for those links from the app.css (both Web App and WebAssembly templates