Appium 4.0: distribute ESM packages

The situation:

• Currently Appium only distributes CJS modules.
• Appium 2.0's minimum required Node.js version is v12.x, which has ESM support.
• Consumers writing ESM would be better off consuming ESM instead of CJS.
• Appium would be better off consuming ESM directly than CJS; it will simplify testing and the importing of local packages. If we are in @appium/foo and import '@appium/bar', we will be importing a transpiled CJS module, which can be painful in a development environment. We should try to get as close to the source as possible.
• The goal is to improve both the user experience and the developer experience.

Proposed solution:

• Publish each package as a ESM package.
• Create a reusable configuration/workflow/whatever for this to happen automatically, and make it easily applicable to multiple existing packages (and new packages).