Make debug tunnel opt-in

[arturpimentel]

What is the purpose of this pull request?

Change toolbelt default behavior so it does not automatically create debug tunnels using websocket

What problem is this solving?

WebSocket support is currently blocking an important infrastructure
migration in VTEX IO. We'll make this an opt-in feature so that we can
better know if people actually depend on this to do their day-to-day
debugging work.

How should this be manually tested?

1. yarn link;
2. vtex link {{app}} -> should link an app without creating a debug tunnel;
3. vtex link {{app}} --debug -> should link an app creating a debug tunnel'.

Screenshots or example usage

None

Types of changes

• Refactor (non-breaking change that only makes the code better)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Requires change to documentation, which has been updated accordingly.

Chores checklist

• Update CHANGELOG.md