rzv CLI 0.11.0: connection commands and clearer errors

rzv 0.11.0 adds gitlab connection commands, and GitLab is not part of V1. Messages for integrations that are not enabled are clearer.

• GitLab is not part of V1 and is not enabled for workspaces yet. The rzv gitlab commands report that it isn't enabled.
• rzv gitlab connectionsLists the connections for the selected workspace.
• rzv gitlab connectOpens the portal page where you set up the integration for the selected workspace.
• rzv gitlab disconnectRemoves a connection. A connection id must match glc_ followed by 24 lowercase hex digits.
• When an integration is not enabled for your account, the command says so in plain words instead of printing the raw error code.
• Downloads are on GitHub at https://github.com/Runzivo/rzv-cli/releases/latest. Release notes are on the same page.