Add EDOT references and tags across observability documentation

[alexandra5000]

This PR:

• Updates product tags to include 'edot-collector' and 'edot-sdk' in various sections.
• Adds notes and tips regarding the use of the Elastic Distributions of OpenTelemetry (EDOT) Collector and SDKs for enhanced telemetry data collection in mobile and Java applications.
• Updates quickstart guides for monitoring hosts and Kubernetes clusters to include EDOT options.

These changes aim to improve clarity and provide users with alternative solutions for telemetry data collection.

Part of #82

Closes #109

LLM usage disclosure: I prompted Claude 4.5 Sonnet in Cursor to find instances where EDOT mentions are missing (according to the issue description and internal conversations about this audit), then reviewed the content manually and fixed Vale linting issues.

[github-actions]

🔍 Preview links for changed docs

• solutions/observability/apm/apm-server/advanced-setup.md
• solutions/observability/apm/get-started.md
• solutions/observability/apm/mobile-service-overview.md
• solutions/observability/get-started/other-tutorials/tutorial-monitor-java-application.md
• solutions/observability/get-started/quickstart-monitor-hosts-with-elastic-agent.md
• solutions/observability/get-started/quickstart-monitor-kubernetes-cluster-with-elastic-agent.md
• solutions/observability/infra-and-hosts/get-started-with-system-metrics.md

[florent-leborgne]

The note/tip is a good idea 👍 (we could even explicitly say that EDOT is the recommended way if that is ultimately why we're adding these, to not leave users wondering why we're suddenly mentioning this)

On the other hand, I don't think we should be adding edot to the frontmatter's product list for cases where the only edot mention is that it can be used alternatively to what's described on the page (when the page itself isn't about edot or describing something using edot)

[alexandra5000]

@florent-leborgne Thanks for your input! You're right, we can be more explicit.

As for the frontmatter, this was mentioned in the original (main) issue for this task, but maybe I did go a bit overboard 😄

[benironside]

A couple of minor suggestions, but LGTM

[bmorelli25]

You link to this page: https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/3983/solutions/observability/apm/get-started but it references APM agents at the top of the page:

Elastic APM receives performance data from your APM agents, validates and processes it, and then transforms the data into Elasticsearch documents.

I think that line ⏫ should mention EDOT alongside APM agents (or just EDOT)

[bmorelli25]

Can you also please add a disclaimer to the description of this Pull Request if you used AI to help with these changes. You can see an example in #3951.

[theletterf]

LGTM! Would love to get @mlunadia 's take on these updates.

[alexandra5000]

Can you also please add a disclaimer to the description of this Pull Request if you used AI to help with these changes. You can see an example in #3951.

@bmorelli25 Right, I added the disclaimer to both PRs where I used AI.