Add "Area" for Oracle Cloud Infrastructure

[geekdave]

So that we can add vendor-specific attributes for Oracle Cloud Infrastructure, we need to update areas.yml and the associated generated file AREAS.md.

This task was assigned to me by @trask and @lmolkova as part of my onboarding as an OTel GitHub Org member, representing Oracle Cloud. See: open-telemetry/community#3187 and CNCF Slack thread: https://cloud-native.slack.com/archives/C041APFBYQP/p1765310083835409

[svrnm]

this should be a semconv issue, right?