docs: add serverless setup instruction to get started (#257)

* docs: add serverless setup instruction to get started

* Better handling for serverless

Author: xrmx

docs/get-started.md

@@ -18,7 +18,7 @@ This guide shows you how to use the Elastic Distribution of OpenTelemetry Python
 Before getting started, you'll need somewhere to send the gathered OpenTelemetry data, so it can be viewed and analyzed. EDOT Python supports sending data to any OpenTelemetry protocol (OTLP) endpoint, but this guide assumes you are sending data to an [Elastic Observability](https://www.elastic.co/observability) cloud deployment. You can use an existing one or set up a new one.
 
 <details>
-<summary><strong>Expand for setup instructions</strong></summary>
+<summary><strong>Expand for Elastic Observability deployment setup instructions</strong></summary>
 
 To create your first Elastic Observability deployment:
 
@@ -28,6 +28,17 @@ To create your first Elastic Observability deployment:
 1. When the deployment is ready, click **Open** to visit your Kibana home page (for example, `https://{DEPLOYMENT_NAME}.kb.{REGION}.cloud.es.io/app/home#/getting_started`).
 </details>
 
+<details>
+<summary><strong>Expand for Elastic Observability Serverless setup instructions</strong></summary>
+
+To create your first Elastic Observability Serverless project:
+
+1. Sign up for a [free Elastic Cloud trial](https://cloud.elastic.co/registration) or sign into an existing account.
+1. Go to <https://cloud.elastic.co/home>.
+1. Click **Create project**.
+1. When the project is ready, click **Open** to visit your Kibana home page (for example, `https://{DEPLOYMENT_NAME}.kb.{REGION}.cloud.es.io/app/home#/getting_started`).
+</details>
+
 <!-- ✅ How to install EDOT Python -->
 ## Install
 
@@ -61,7 +72,7 @@ After installing EDOT Python, configure and initialize it to start sending data
 <!-- ✅ Provide _minimal_ configuration/setup -->
 ### Configure EDOT Python
 
-To configure EDOT Python, at a minimum you'll need your Elastic Observability cloud deployment's OTLP endpoint and
+To configure EDOT Python, at a minimum you'll need your Elastic Observability cloud OTLP endpoint and
 authorization data to set a few `OTLP_*` environment variables that will be available when running EDOT Python:
 
 * `OTEL_RESOURCE_ATTRIBUTES`: Use this to add a service name that will make it easier to recognize your application when reviewing data sent to Elastic.
@@ -77,16 +88,16 @@ You can find the values of the endpoint and header variables in Kibana's APM tut
 1. Scroll down and select the **OpenTelemetry** option.
 1. The appropriate values for `OTEL_EXPORTER_OTLP_ENDPOINT` and `OTEL_EXPORTER_OTLP_HEADERS` are shown there.
 
-Here's an example:
+Here's an example for sending data to an Elastic Cloud deployment:
 
 ```sh
-export OTEL_RESOURCE_ATTRIBUTES=service.name=<app-name>
+export OTEL_RESOURCE_ATTRIBUTES=service.name=<app-name>,service.version=<app-version>,deployment.environment=production
 export OTEL_EXPORTER_OTLP_ENDPOINT=https://my-deployment.apm.us-west1.gcp.cloud.es.io
 export OTEL_EXPORTER_OTLP_HEADERS="Authorization=Bearer P....l"
 ```
 
 > [!NOTE]
-> Alternatively, you can use an [APM agent key](https://www.elastic.co/guide/en/observability/current/apm-api-key.html) to authorize requests to an Elastic Observability endpoint. APM agent keys are revocable, you can have more than one of them, and you can add or remove them without restarting APM Server.
+> Alternatively on deployments, you can use an [APM agent key](https://www.elastic.co/guide/en/observability/current/apm-api-key.html) to authorize requests to an Elastic Observability endpoint. APM agent keys are revocable, you can have more than one of them, and you can add or remove them without restarting APM Server.
 >
 > To create and manage APM Agent keys in Kibana:
 >
@@ -98,6 +109,17 @@ export OTEL_EXPORTER_OTLP_HEADERS="Authorization=Bearer P....l"
 > export OTEL_EXPORTER_OTLP_HEADERS="Authorization=ApiKey TkpXUkx...dVZGQQ=="
 > ```
 
+And here's an example for sending data to an Elastic Cloud serverless project:
+
+```sh
+export OTEL_RESOURCE_ATTRIBUTES=service.name=<app-name>,service.version=<app-version>,deployment.environment=production
+export OTEL_EXPORTER_OTLP_ENDPOINT=https://my-deployment.apm.us-west1.gcp.cloud.es.io
+export OTEL_EXPORTER_OTLP_HEADERS="Authorization=ApiKey B....="
+```
+
+> [!NOTE]
+> You'll be prompted to create an API key during the Elastic Cloud serverless project onboarding. Refer to the [Api keys documentation](https://www.elastic.co/guide/en/serverless/current/api-keys.html) on how to manage them.
+
 <!-- ✅ Start sending data to Elastic -->
 ### Run EDOT Python