feat: install core tools automatically when needed (closes #353)

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Best description is a short demo:

🎉

What this PR does:

• Check if Core Tools are installed globally
• If not or if the global Core Tools version doesn't match the required Node.js runtime, it will install a local version shared among all CLI instances (installed in ~/.swa/core-tools
• Multiple major versions of local Core Tools can coexist, for example v3 if you have a Node v12 project and v4 for a Node v16 projects (if you're using NVM for example)
• Use local Core Tools version when available

[sinedied]

All comments should have been resolved, there're now more testing code that actual code 😅