docs: make opentelemetry-proto README consistent with other components (#3445)

Co-authored-by: Lalit Kumar Bhasin <lalit_fin@yahoo.com>
Co-authored-by: Cijo Thomas <cijo.thomas@gmail.com>

Author: 3 people

opentelemetry-proto/README.md

@@ -1,13 +1,57 @@
+# OpenTelemetry Proto
+
 ![OpenTelemetry — An observability framework for cloud-native software.][splash]
 
 [splash]: https://raw.githubusercontent.com/open-telemetry/opentelemetry-rust/main/assets/logo-text.png
 
-# OpenTelemetry Proto
-This crate contains generated files from [opentelemetry-proto](https://github.com/open-telemetry/opentelemetry-proto)
-repository and transformation between types from generated files and types defined in [opentelemetry](https://github.com/open-telemetry/opentelemetry-rust/tree/main/opentelemetry).
+This crate contains generated files from
+[opentelemetry-proto](https://github.com/open-telemetry/opentelemetry-proto)
+repository and transformations between types from generated files and types
+defined in
+[opentelemetry](https://github.com/open-telemetry/opentelemetry-rust/tree/main/opentelemetry).
+
+[![Crates.io: opentelemetry-proto](https://img.shields.io/crates/v/opentelemetry-proto.svg)](https://crates.io/crates/opentelemetry-proto)
+[![Documentation](https://docs.rs/opentelemetry-proto/badge.svg)](https://docs.rs/opentelemetry-proto)
+[![LICENSE](https://img.shields.io/crates/l/opentelemetry-proto)](https://github.com/open-telemetry/opentelemetry-rust/blob/main/opentelemetry-proto/LICENSE)
+[![GitHub Actions CI](https://github.com/open-telemetry/opentelemetry-rust/workflows/CI/badge.svg)](https://github.com/open-telemetry/opentelemetry-rust/actions?query=workflow%3ACI+branch%3Amain)
+[![codecov](https://codecov.io/gh/open-telemetry/opentelemetry-rust/branch/main/graph/badge.svg)](https://codecov.io/gh/open-telemetry/opentelemetry-rust)
+[![Slack](https://img.shields.io/badge/slack-@cncf/otel/rust-brightgreen.svg?logo=slack)](https://cloud-native.slack.com/archives/C03GDP0H023)
+
+## Overview
+
+OpenTelemetry is an Observability framework and toolkit designed to create and
+manage telemetry data such as traces, metrics, and logs. OpenTelemetry is
+vendor- and tool-agnostic, meaning that it can be used with a broad variety of
+Observability backends, including open source tools like [Jaeger] and
+[Prometheus], as well as commercial offerings.
+
+OpenTelemetry is *not* an observability backend like Jaeger, Prometheus, or other
+commercial vendors. OpenTelemetry is focused on the generation, collection,
+management, and export of telemetry. A major goal of OpenTelemetry is that you
+can easily instrument your applications or systems, no matter their language,
+infrastructure, or runtime environment. Crucially, the storage and visualization
+of telemetry is intentionally left to other tools.
 
 *[Supported Rust Versions](#supported-rust-versions)*
 
+[Prometheus]: https://prometheus.io
+[Jaeger]: https://www.jaegertracing.io
+
+### What does this crate contain?
+
+This crate provides auto-generated Protobuf types from the [OpenTelemetry
+protocol specification](https://github.com/open-telemetry/opentelemetry-proto),
+along with conversion implementations between these generated types and the
+types defined in the
+[opentelemetry](https://crates.io/crates/opentelemetry) crate. It is used
+internally by exporters such as
+[opentelemetry-otlp](https://crates.io/crates/opentelemetry-otlp) to serialize
+and deserialize telemetry data.
+
+## Getting started
+
+See [docs](https://docs.rs/opentelemetry-proto).
+
 ## Release Notes
 
 You can find the release notes (changelog) [here](https://github.com/open-telemetry/opentelemetry-rust/blob/main/opentelemetry-proto/CHANGELOG.md).
@@ -23,4 +67,4 @@ before it will always be supported. For example, if the current stable compiler
 version is 1.49, the minimum supported version will not be increased past 1.46,
 three minor versions prior. Increasing the minimum supported compiler version
 is not considered a semver breaking change as long as doing so complies with
-this policy.
+this policy.