PR Checklist

• The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/tools/notes/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.
• You have signed the CLA.
• 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?

Users are prevented from using npm install --ignore-scripts because any ns plugin that requires hooks utilises post install events to install the hooks.

What is the new behavior?

This PR provides the hooks command to manage plugin hooks.

PR provides:

Usages

• Modify/Create .npmrc in the project root adding ignore-scripts=true
• After npm i run ns hooks install

For extra peace of mind:

Run ns hooks lock and ns hooks install will fail if any of the hooks have changed.