Add link to 'Swag' store in global footer

[coffee2code]

The WordPress Swag Store long had a link on the homepage of w.org until the homepage redesign launched in Aug 2022. As it stands now, there isn't a notable link to the Swag store. Per matt, a link to the store should be added to the footer.

The current footer is balanced across its 5 columns with 4 links each, which would become unbalanced by the addition of this link. As a solution to that, I am also in favor of the proposal in #134 that adds a link each to the first 4 columns: Jobs, Mobile(?), Photos, Openverse (in that order). (I think at the time "Mobile" was present and "Learn" wasn't, but that has since changed. Not sure if it should be reintroduced.) However, the Jobs link should instead go into the last column. The new links would all be conceptually appropriate for each column. (Discussion for these changes can continue in #134.)

The first column (left empty in the aforementioned ticket after my proposed change) would ideally accommodate "Swag".