feat: Export semantic attribute keys from SDK packages

[Lms24]

Given users should make use of attributes when performing custom instrumentation, this PR adds exports for our semantic attributes keys from the SDK packages so that users don't have to install @sentry/core explicitly.

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser (incl. Tracing, Replay, Feedback) - Webpack (gzipped)	77.79 KB (-0.21% 🔽)
@sentry/browser (incl. Tracing, Replay) - Webpack (gzipped)	69.04 KB (-0.2% 🔽)
@sentry/browser (incl. Tracing, Replay with Canvas) - Webpack (gzipped)	72.97 KB (-0.2% 🔽)
@sentry/browser (incl. Tracing, Replay) - Webpack with treeshaking flags (gzipped)	62.66 KB (-0.22% 🔽)
@sentry/browser (incl. Tracing) - Webpack (gzipped)	33.23 KB (-0.44% 🔽)
@sentry/browser (incl. browserTracingIntegration) - Webpack (gzipped)	33.13 KB (-0.31% 🔽)
@sentry/browser (incl. Feedback) - Webpack (gzipped)	31.16 KB (0%)
@sentry/browser (incl. sendFeedback) - Webpack (gzipped)	31.16 KB (0%)
@sentry/browser - Webpack (gzipped)	22.43 KB (0%)
@sentry/browser (incl. Tracing, Replay, Feedback) - ES6 CDN Bundle (gzipped)	76.1 KB (+0.02% 🔺)
@sentry/browser (incl. Tracing, Replay) - ES6 CDN Bundle (gzipped)	67.62 KB (+0.04% 🔺)
@sentry/browser (incl. Tracing) - ES6 CDN Bundle (gzipped)	33.6 KB (+0.04% 🔺)
@sentry/browser - ES6 CDN Bundle (gzipped)	24.7 KB (+0.28% 🔺)
@sentry/browser (incl. Tracing, Replay) - ES6 CDN Bundle (minified & uncompressed)	212.89 KB (-0.02% 🔽)
@sentry/browser (incl. Tracing) - ES6 CDN Bundle (minified & uncompressed)	101.51 KB (-0.05% 🔽)
@sentry/browser - ES6 CDN Bundle (minified & uncompressed)	74.03 KB (+0.28% 🔺)
@sentry/browser (incl. Tracing) - ES5 CDN Bundle (gzipped)	36.87 KB (+0.11% 🔺)
@sentry/react (incl. Tracing, Replay) - Webpack (gzipped)	69.41 KB (-0.21% 🔽)
@sentry/react - Webpack (gzipped)	22.46 KB (0%)
@sentry/nextjs Client (incl. Tracing, Replay) - Webpack (gzipped)	87.09 KB (-0.26% 🔽)
@sentry/nextjs Client - Webpack (gzipped)	50.36 KB (-0.16% 🔽)
@sentry-internal/feedback - Webpack (gzipped)	17.1 KB (0%)