disable or remove phone home diagnostics/telemetry

[iliana]

CockroachDB phones home to two endpoints:

cockroach/pkg/server/diagnostics/diagnostics.go

Lines 33 to 59 in 4088380

	// updatesURL is the URL used to check for new versions. Can be nil if an empty
	// URL is set.
	var updatesURL *url.URL
	const defaultUpdatesURL = `https://register.cockroachdb.com/api/clusters/updates`
	// reportingURL is the URL used to report diagnostics/telemetry. Can be nil if
	// an empty URL is set.
	var reportingURL *url.URL
	const defaultReportingURL = `https://register.cockroachdb.com/api/clusters/report`
	func init() {
	var err error
	updatesURL, err = url.Parse(
	envutil.EnvOrDefaultString("COCKROACH_UPDATE_CHECK_URL", defaultUpdatesURL),
	)
	if err != nil {
	panic(err)
	}
	reportingURL, err = url.Parse(
	envutil.EnvOrDefaultString("COCKROACH_USAGE_REPORT_URL", defaultReportingURL),
	)
	if err != nil {
	panic(err)
	}
	}

The web console also phones home in a few places, identified by COCKROACHLABS_ADDR:

cockroach/pkg/ui/workspaces/db-console/src/util/cockroachlabsAPI.ts

Lines 55 to 64 in 4088380

	export function versionCheck(
	request: VersionCheckRequest,
	timeout?: moment.Duration,
	): Promise<VersionList> {
	return timeoutFetch(
	`${COCKROACHLABS_ADDR}/api/clusters/updates?uuid=${request.clusterID}&version=${request.buildtag}`,
	null,
	{ timeout },
	);
	}

We want to remove this for two reasons:

1. In the Oxide product, CockroachDB runs in a zone with no external network reachability. There's no point to spending cycles on attempting to phone home.
2. It honestly seems rude to send CRL telemetry for a build of a four-year-old version they have nothing to do with and no control over, particularly given the number of instances we start (order of ~1000) during a normal integration test run of the Oxide control plane.

It is simple enough to remove the URLs or replace them with invalid hostnames, but I think it'd be better to delete the code altogether; no sense in maintaining what you can't or won't use.