How to create a custom gmail design and template

Right, catchy title aside, I wanted to send an email recently from my Gmail account but I wanted to add a footer that essentially required a table for layout. Except Gmail (and Google Inbox AFAIK) rich editbox doesn’t let you do more complicated styling aside from bold, italic and font selection.
When I first started searching, I found a number of Chrome plugins that would let me insert some nice templates, but it required giving other sites full access to my inbox… :hears-crickets: so no, that wasn’t going to happen. So here’s how I got around it.