feat: add pings for IDE extensions usage
Created by: abeatrix
This is the PR for RFC 577
To close https://github.com/sourcegraph/sourcegraph/issues/29124
This PR also adds a new EventSource type IDEEXTENSION to log all ide-extensions-related events as suggested in RFC 547
PR to change schema: https://github.com/sourcegraph/analytics/pull/368 (waiting to be approved)