Web error telemetry (passive Sentry)

[lampholder]

We don't currently have visibility on errors occurring in riot web 'in the wild' - information that could be used both to capture, diagnose and fix problems that users experience (but might not report), and to track our progress against reducing the incidence of known problems such as Unable To Decrypt failures.

I'd like for such errors to be reported to a sentry instance (or similar) - obvs this could be configurable per riot deploy, and data should be anonymised (and probably opt-in, too).

[novocaine]

We have Sentry configured to receive Rageshake data, see matrix-org/matrix-react-sdk#6597

In order to fulfil this ticket and make that reporting happen as part of passive telemetry, we need to strip more data out of the Sentry reporting to ensure it complies to our description of what we track, then have Sentry capture all errors if tracking/telemetry consent has been given by the user