Dashify HTML ids, as is convention.
Use the jQuery DOM ready shorthand to allow admin_home.js and season_data_rendering.js to be loaded with the rest of the js files.
Move javascript includes into base.html.

This will help us get to the point where we can load all of the js files in one big, minimized file.
Transpile JSX instead of using the in-browser transformer.
Made a few improvements where the linter flagged problems in the js.