Requirements

With this PR we added better-named protos and endpoints. We should serve both of these for a while before removing the old ones in 1.0. See all the protos here: https://buf.build/open-feature/flagd

@bacherfl did a POC here: bacherfl#1

Note this should be done for both the flagd-proxy (sync.proto) and flagd itself (evaluation.proto).

See reasoning for new naming here: #948

cc @Kavindu-Dodan @bacherfl