freetube: add requires_rosetta, quit and fixups

[toobuntu]

Important: Do not tick a checkbox if you haven’t performed its action. Honesty is indispensable for a smooth review process.

In the following questions <cask> is the token of the cask you're submitting.

After making any changes to a cask, existing or new, verify:

• The submission is for a stable version or documented exception.
• brew audit --cask --online <cask> is error-free.
• brew style --fix <cask> reports no offenses.

Additionally, if adding a new cask:

• Named the cask according to the token reference.
• Checked the cask was not already refused.
• Checked the cask is submitted to the correct repo.
• brew audit --cask --new <cask> worked successfully.
• HOMEBREW_NO_INSTALL_FROM_API=1 brew install --cask <cask> worked successfully.
• brew uninstall --cask <cask> worked successfully.

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• Add caveat: requires_rosetta
• Add depends_on: macos >= high_sierra
• Add uninstall: quit
• Modify zap: include extra path

[toobuntu]

The motivation for this is FreeTubeApp/FreeTube#2786 (comment):

Basically it's a lot easier for everyone to just run the x64 build of FreeTube through Rosetta 2.

While there, audit complained about a missing minimum OS version, createzap found an additional path, and I added uninstall quit.