feat(rum): Add ability to query measurements

[Zylphrex]

This change makes the measurement columns available to Sentry. Specifically, a
measurement x can be queried under the name measurements.x.

All measurements are of the type number, and are treated as such. Furthermore,
fp, fcp, lcp, and fid are special cased to be treated as durations as
well.

Measurements can also be used under aggregate functions, provided they are of
the appropriate types.

This change depends on getsentry/relay/pull/724 and getsentry/relay#785

[vercel]

This pull request is being automatically deployed with Vercel (learn more).
To see the status of your deployments, click below or on the icon next to each commit.

[github-actions]

size-limit report

Path	Size
public/app.js	235.47 KB (0%)
public/vendor.js	448.17 KB (0%)