[FIX] #41560 UI: Footer Link Colours

[thibsy]

Hi folks,

This PR introduces two less variables @il-footer-link-color and @il-footer-link-hover-color which can be used to style links differently inside the footer. I defaulted them to the @il-link-color and @il-link-hover-color variables. This solutions is needed to address a mantis issue, which describes contrast issues with dark footer background colours.

While adding these variables I also noticed, the @il-link-hover-color was never assigned, so I have added this with the PR as well.

Kind regards, @thibsy