feat: add env check hook in order to allow cloud builds without any native local setup

[DimitarTachev]

PR Checklist

• The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/CONTRIBUTING.md#commit-messages.
• There is an issue for the bug/feature this PR is for. To avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it.
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• All existing tests are passing: https://github.com/NativeScript/nativescript-cli/blob/master/CONTRIBUTING.md#contribute-to-the-code-base
• Tests for the changes are included.

What is the current behavior?

There's no way to override the CLI env checks through a hook.

What is the new behavior?

We are able to override the CLI env checks through a before checkEnvironment hooks.

Related to: #5210

[DimitarTachev]

test misc