Read browser monitoring

Runs a LogQL query over the app's own logs, kept for seven days, and returns Loki's answer unchanged: lines for a log query, series for a metric query. Streams: `{container="<service>"}` is each compose service's own output, with `pod` and a `detected_level` (error, critical, fatal, warn, info, debug, trace or unknown) to filter on as `| detected_level=~"error|critical|fatal"`; `{container="_events"}` holds the Kubernetes events about the app's objects as JSON (`kind`, `name`, `reason`, `type`, `msg`, `count`); `{container="_access", service="<service>"}` is the ingress access log of the service the app's address routes to, as Traefik's JSON (`RequestMethod`, `RequestPath`, `DownstreamStatus`, `Duration` in nanoseconds, `request_User-Agent`), with `route`, `method` and `status` as fields; and `{container="_rum", kind="pageview"}` with kinds `vital`, `error`, `net`, `signal`, `custom` and `session` holds browser monitoring, with `page`, `session`, `device`, `browser`, `os` and `country` as fields. Session recordings are kept apart: getBrowserSessionReplay reads them, with the developer role. A query the store refuses comes back with the store's own status and `error`. The path is the store's own, so a Grafana data source can point here too.