reorganize starter-files.js, which currently doesn't consistently follow any rules

[retabak]

This work is to be done on a starter-files branch.

We need a starter-files folder in shared/langs/en-us.

In the folder we would like the following files:

• editors
• algebra
• algebra-desmos
• algebra2
• algebra2-desmos
• core
• data-science
• data-science-desmos
• early-math
• hour-of-code
• projects
• reactive

Those files will be formatted like the starter-files.js file.

In the end, all of these files will get stitched together to do the same work that the current starter-files.js file is doing.

For example, Algebra will still contain something similar to

const allStarterFiles = {
...Flags,
...GameBasics,
...MoreAlg,
}

The goal of this issue is to make the file(s) more manageable for authors to interact with.

Once Dorai has set up the files, authors will be responsible for populating them with the appropriate files.

[flannery-denny]

@ds26gte I can't remember. Did anything happen with this yet?