feat(ioredis): prototype running tests in ESM mode

[pichlermarc]

Which problem is this PR solving?

This is a prototype for running esm tests using our existing tests, based on my comment on #1731.

This PR is not intended for merging, but rather to illustrate how we could run ESM tests if we'd want to have full coverage with our existing tests.

• esm.mocharc.json is used by the esm tests, and specifies both ts-node and otel esm loaders
• npm run prepare:test:esm
  • patches the mocha cli by removing an if statement that checks if it's being called from the command line, which evaluates to false due to import-in-the-middle
  • sets the type to module in package.json, I've not found a way around this yet.
• npm run test:esm:local lets one run the tests in ESM mode (the instrumentation code is also transpiled to ESM mode, which does not 100% reflect real-life as we don't publish ESM with the npm package)
  • I've addd the log statement from test(ioredis): test ioredis ESM usage #1752 so that we have a similar log output here
  • we need to use import in the tests so that they also work with ESM, it transpiles to require for cjs, so that should be ok.
• restore:test:cjs sets the type back to commonjs again and un-patches mocha.

This is quite a prototype setup; I think if we'd want to introduce something like this, we'd need adapt some of this to be less fragile.

[pichlermarc]

Unassigning as this PR is for illustration purposes only.

[pichlermarc]

Closing as #1735 has now been merged.