Update Frontend Tooling

@jldust - I'm sure we'll want to talk about the sweeping changes that I've made prior to merging. I'm happy to go through everything :)

@pixelwhip / @jldust - I've refactored all SASS files according to @pixelwhip's feedback. This includes adding a breakpoint mixin and replacing any reference that uses the removed NPM library with the correct mixin. I've also combed through the SASS and resulting CSS and could not finding any need for a font-size transformer – all font sizes were hard-written into ems already.

@pixelwhip - Where the only updates to the const variable declarations? Those should all be fixed up now :)

@pixelwhip / @jldust - I've removed the tailwind file and references and have also updated the naming convention of breakpoint mixins from up/down to min/max.

@pixelwhip / @jldust - I've added back the configuration files, both upgrading them and adding documentation to them. I also updated the readme file with more documentation.