[Serverless-Init] Reduce in-container vs sidecar confusion; explain serverless-init image tags

[nhulston]

What does this PR do? What is the motivation?

• In sidecar vs in-container comparison, remove the confusing "Observing multiple containers not supported for in-container".
  • Customers were understandably getting confused and thought this meant that the in-container approach is not supported when their app scales to multiple instances.
  • Rather, this was meant to explain that if they had multiple sidecar containers in a single instance, the sidecar approach could collect telemetry from all sidecar containers in that single instance.
  • I think it's best to remove this, because it is extremely rare that customers will have more than one container per instance, and we just want to avoid confusion.
• Add image tag explanations to sidecar docs
• Avoid referencing serverless-init:latest or serverless-init:1 references in docs. Rather, the customer should choose whatever image tag they want to use.

Merge instructions

Merge readiness:

• Ready for merge

Additional notes

[github-actions]

Preview links (active after the build_preview check completes)

Modified Files

• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/azure_container_apps/
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/azure_container_apps/in_container/dotnet
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/azure_container_apps/in_container/go
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/azure_container_apps/in_container/java
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/azure_container_apps/in_container/nodejs
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/azure_container_apps/in_container/php
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/azure_container_apps/in_container/python
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/azure_container_apps/in_container/ruby
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/azure_container_apps/sidecar/dotnet
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/azure_container_apps/sidecar/go
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/azure_container_apps/sidecar/java
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/azure_container_apps/sidecar/nodejs
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/azure_container_apps/sidecar/php
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/azure_container_apps/sidecar/python
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/azure_container_apps/sidecar/ruby
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/google_cloud_run/containers/
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/google_cloud_run/containers/in_container/dotnet
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/google_cloud_run/containers/in_container/go
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/google_cloud_run/containers/in_container/java
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/google_cloud_run/containers/in_container/nodejs
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/google_cloud_run/containers/in_container/php
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/google_cloud_run/containers/in_container/python
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/google_cloud_run/containers/in_container/ruby
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/google_cloud_run/containers/sidecar/dotnet
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/google_cloud_run/containers/sidecar/go
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/google_cloud_run/containers/sidecar/java
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/google_cloud_run/containers/sidecar/nodejs
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/google_cloud_run/containers/sidecar/php
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/google_cloud_run/containers/sidecar/python
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/google_cloud_run/containers/sidecar/ruby
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/google_cloud_run/jobs/dotnet
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/google_cloud_run/jobs/go
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/google_cloud_run/jobs/java
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/google_cloud_run/jobs/nodejs
• https://docs-staging.datadoghq.com/nicholas.hulston/serverless-init-fixes/serverless/google_cloud_run/jobs/python