Include `event.contexts.device.processor_count` for browser and node

[timfish]

Problem Statement

Most platforms now have a way to get the CPU count.

Solution Brainstorm

In browsers navigator.hardwareConcurrency has been around for a while. Safari apparently caps this as 2 for iOS and 8 for macOS.

Node.js has had os.cpus() since pre v1.

[AbhiPrasad]

We’ve been tracking this as a span on transactions for performance monitoring.

sentry-javascript/packages/tracing/src/browser/metrics/index.ts

Line 386 in 7a0dc54

transaction.setTag('hardwareConcurrency', String(navigator.hardwareConcurrency));