Remove gulp

[david-ma]

Remove gulp. Replace with npm scripts.

Currently gulp is gives me:

• Developing environment, with browser sync
• Compiles SCSS in src to dist
• Compiles Typescript in src to dist
• Watches any changes on the Typescript or SCSS, compiles them, then tells browsersync.

Also has:

• A "publish" function, which copies files from dist to public and/or docs for hosting stuff on github pages.
• Build function. Not used much.
• Also handles combining things from thalia/src to thalia/websites/<project name>/dist