feat(cli): Add a command to ensure all necessary tools are installed to run Backstage locally

Feature Suggestion

Running a Backstage app locally needs a few things installed in your local computer, yarn and node being just a few of them. Since Backstage apps are platforms on which developers contribute, we need to ensure that it’s easy for them to run Backstage locally.

There should be a command in backstage-cli, which they can run as part of “getting started” to ensure that they have all the necessary tools for running a Backstage app, installed in their system.

Possible Implementation

• Add a command here https://github.com/backstage/backstage/tree/master/packages/cli/src/commands which uses some “command-exists” library to make sure few executables are installed. And optionally prints out installation instructions in console.
• Update the root package.json in the create-app template as well as backstage/backstage repository to add this command as a script.

Context

https://github.com/backstage/backstage/pull/5152/files had started this discussion long time ago. https://github.com/backstage/backstage/pull/6477 just now, pushed me into creating this issue.

[iamrajiv]

@OrkoHunter I want to work on this.

[OrkoHunter]

Closing in favor of #6519