Runtime Metrics: Deno support

[chargome]

Description

Deno does not inherit from node-core, so a separate integration is needed: packages/deno/src/integrations/denoRuntimeMetrics.ts.

Deno has stable native APIs for all target metrics (Deno.memoryUsage(), Deno.systemMemoryInfo(), Deno.loadavg()) plus full Node compat for event loop
APIs since v2.1.0.

[linear-code]

JS-1957