feat: add new command 'data:pg:levels' (W-21411625)

[sbosio]

Summary

Here we add a new data:pg:levels command, which shows available levels to be used with Heroku Postgres Advanced databases.

The implementation was mostly copied from https://github.com/heroku/heroku-cli-plugin-data-beta/pull/176, converted to @oclif/core v4 and ESM, with minor refactor and fixes.

Type of Change

Breaking Changes (major semver update)

• Add a ! after your change type to denote a change
• that breaks current behavior

Feature Additions (minor semver update)

• feat: Introduces a new feature to the codebase

Patch Updates (patch semver update)

• fix: Bug fix
• deps: Dependency upgrade
• revert: Revert a previous commit
• chore: Change that does not affect production code
• refactor: Refactoring existing code without changing behavior
• test: Add/update/remove tests

Testing

Steps

1. Checkout this branch and run npm install && npm run build.
2. Create a new advanced database on your test app using
   ./bin/run data:pg:create -a <test-app-name> --as ADVANCED_DB
3. The following command should hang and wait until the database is available, polling every 15 seconds:
   ./bin/run data:pg:wait ADVANCED_DB -a <test-app-name> --wait-interval 15

Screenshots (if applicable)

Related Issues

GUS work item: W-21411625