Refactored all HTTP requests to use axios

[SundeepChand]

Fixes #975

I have verified that this pull request:

• has no linting errors (npm run lint)
• is from a uniquely-named feature branch and has been rebased on top of the latest develop branch. (If I was asked to make more changes, I have made sure to rebase onto develop then too)
• is descriptively named and links to an issue number, i.e. Fixes #123

Hello @catarak, please review this. I have not been able to test fetch-examples-ml5.js as I could not find the EDITOR_API_ACCESS_TOKEN.

[release-com]

Release Environments

p5.js-web-editor
app-tedfbad-p5-js-web-editor.releaseapp.io

[catarak]

I can't even tell you the joy this brings me. Feels so good to clean up code! Since this is touching on some fundamental stuff I'm going to test this carefully.

[catarak]

Everything seems to be working for me except for fetching the ml5 examples. However, this could be because of some necessary changes in #1762—I think I'm going to get that one merged in first, handle the git conflicts, and see if that fixes it.

[SundeepChand]

I've tested examples-ml5.js & its working for me now.

[catarak]

The ml5 script is also working for me! All of the other functionality this touches also is working for me:

• p5.js example fetching script
• generative design example fetching script
• downloading sketches
• using sketch assets by url
• syntax highlighting script