It seems like we've ended up with a bit of a mixture of 2 and 4 space indentation in the codebase. After some discussion it seems like no one really minds which we use, so long as it's consistent. I've ended up picking two-space indentation since that seems to be the community preference.

I've added an editorconfig file which many editors will use to automatically determine the indentation style of new files.

I've also replaced the TSLint indent rule (which is broken) with ter-indent from the tslint-eslint-rules package. Ideally we should switch entirely from TSLint to ESLint, but it seems best to do that in a follow-up pull request.

Merge / deployment checklist

• Run test builds as necessary. Can be on this repository or elsewhere as needed in order to test the change - please include links to tests in other repos!
  • CodeQL using init/analyze actions (N/A)
  • 3rd party tool using upload action (N/A)
• Confirm this change is backwards compatible with existing workflows. (N/A)
• Confirm the readme has been updated if necessary. (N/A)