GUI: add telemetry

As a developer I would like to ensure we quantitatively understand how our GUI is used.

To support this, it would be useful to add instrumentation using e.g. OpenTelemetry.

Suggested high-level telemetry events would include things like:
- Perspective changes
- Opening views (e.g. OPIs)
- Dialog entries & exits
- Any other 'obvious' places where it's beneficial to add telemetry

Adding telemetry *everywhere* would take a long time; this ticket is to get a minimum useful set of telemetry events set up, which we can later build on as and when needed.

### Acceptance criteria
- [ ] Telemetry for the above events added to GUI
- [ ] Suitable server set up to receive these telemetry events
- [ ] Suitable server set up to display these telemetry events
- [ ] Ensure that gui still works if telemetry server is unreachable