Monitoring: live tracing and live metrics streams, and their tokens (MON-20 to MON-24)

GET /api/token/tracing and /api/token/metrics issue a 60-second token for
holders of liveTracing or liveMetrics outside a tenant. /api/live/tracing
streams event: trace frames of x:TraceEvents, never raw I/O, filtered by
text or by key, with a ping while idle; /api/live/metrics streams event:
metrics frames of current totals every interval. At most eight streams run
per node, each for 30 minutes. Upstream's documented paths are aliases.

crates/http/src/lib.rs

@@ -10,6 +10,7 @@ pub mod api;
 pub mod auth;
 pub mod branding; // inbuxa: branding
 pub mod form;
+pub mod live; // inbuxa: monitoring (MON-20 to MON-24)
 pub mod request;
 
 use common::Inner;