Create layout components for use across product pages

[jakewheeler]

Work Summary

During work on the eCR Viewer page layout we discussed that it would be useful to create layout components -- reusable components that build up the layout of the page (grids, flex containers, etc.) so that we can focus primarily on adding content. This also ensures that the layouts of each page are consistent across all of them and any further styling changes will be reflected on every product page.

For this task, we should build these layout components. We should also use these components for the eCR Viewer product page and, ideally, one new product page (as a means of testing).