Improve js linting setup

What does this MR do?

The linter used to only lint client/* files, now it also lints src/Modules/{webpackModule...}/**/*.js.

I did this by wrapping the standard command to specify the files that we want it to apply to, it's in bin/standard and passes arguments through so you can use it just the same as the normal one.

I added yarn fix command to do whatever fixes standardjs can do.

Also, the list of webpack'd modules are in client/modules.js now (as it's loaded by bin/standard and the webpack config).

I removed the index map stuff too as there is no longer an index map...

How confident are you it won't break things if deployed?

Very :)

Links to related issues

Checklist

• added a test, or explain why one is not needed/possible...
• no unrelated changes
• asked someone for a code review
• joined #foodsharing-beta channel at https://slackin.yunity.org
• added an entry to CHANGELOG.md (description, merge request link, username(s))