Enhance analytics to track coc use

[kanej]

We want to be able to tell if people are using the language server from vim/neovim.

Our goal is:

• user opts in through notification, though experiment with better messages (within the constraints)
• investigate whether coc will give the equivalent of a machine id (as vscode does) - so we can anonymously track whether a session is on the same ls instance
• update the google analytics to differentiate between standalone and vscode (maybe leverage different browser values)
• update sentry to include the context of the machine id and whether standalone of vscode
• Update the coc event handlers so that changing the telemetry setting is reflected on the language server