Change og:image to new branding, with more robust tags

Status

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What does this PR do?

This changes the implementation of the og:image opengraph tag. It does this primarily to update the logo that gets loaded - from the old branding to the new branding. Along the way, it also improves a few things about how the image is called - adding explicit sizing, and making the path to the image directory-agnostic.

Helpful background context (if appropriate)

The directory-agnostic work is primarily happening in #303 - but given that this branch is changing this line, it didn't make sense to me to not do this part of that work now. I'll refactor that work if this merges to avoid a conflict.

How can a reviewer manually see the effects of these changes?

Our staging site is blocked from the outside, so no social previews will work until the code hits production. Instead, I would recommend looking at the source code and comparing what is there against the OG documentation.

What are the relevant tickets?

https://mitlibraries.atlassian.net/browse/NTI-565

Todo:

[x] Stakeholder approval

MITLibraries / MITlibraries-parent