how to: "uninstall dvc" for both binary and pip packages

[efiop]

[shcheklein]

Related discussion: https://discordapp.com/channels/485586884165107732/485596304961962003/574941227624169492

For Mac (installed from pkg):

$ which dvc
/usr/local/bin/dvc -> /usr/local/lib/dvc/dvc

$ ls -la /usr/local/bin/dvc
/usr/local/bin/dvc -> /usr/local/lib/dvc/dvc

sudo rm -f /usr/local/bin/dvc
sudo rm -rf /usr/local/lib/dvc
sudo pkgutil --forget com.iterative.dvc

[jorgeorpinel]

Closing in favor of #702