Add support for comments in project settings file

[BrodBlox09]

Fixes #1101

• npm run test succeeds.
• npm run lint succeeds.
• Appropriate changes to README are included in PR.

[BrodBlox09]

project.updateSettings() is called when a script is cloned or created, when the user is prompted to update the GCP project ID and enters a new one, and when an MCP server is created. project.updateSettings() would clear any existing comments from the .clasp.json file, but should only be an issue when the user is prompted to update the GCP project ID. Though, "filePushOrder" is always reset to [] on every call to project.updateSettings() anyways, so some information is already lost.