[Enhancement] Migrate away from bower

[chriscoffee]

After a long debate back in 2016-17 bower was deprecated by it's owners in favour of using webpack/yarn/npm bower/bower#2298

We'll need to drop bower components that we include and move to just using npm or webpack if we want all the extra functionality it provides.

You can read move about this here https://snyk.io/blog/bower-is-dead/ for example.

[mattstratton]

I noticed a branch in your fork where you have been working on this...we should discuss how gulp is used.

The main default task is for building the site content, so it should NOT build scss files, js, etc. Those are all built into the theme itself and rendered as artifacts; I used to have a set of "dev" gulp tasks which would run these things and also run watch. Previously when I was the only one working on this, I used CodeKit to build the SASS and concatenate the javascript, etc.

The image resizing, etc, really doesn't need to be run in the theme. This is what is run during the production build of the site, what creates the various sizes of images, processes the HTML to put in srcset attributes, etc.

I've also upgraded to gulp 4, so your fork is out of date :)