Add reference page for default log component templates

[alexandra5000]

This PR adds a new reference page under /solutions/observability/logs/ that documents the default component templates applied to logs data streams.

Closes #1863

[github-actions]

🔍 Preview links for changed docs

• solutions/observability/logs/logs-index-template-defaults.md
• solutions/observability/logs/logs-index-template-reference.md

[mdbirnstiehl]

Nice work, and thanks for putting this together! I've added a few suggestions, let me know if you have any questions or concerns, and I'll be happy to discuss.

[gbamparop]

Thanks for working on this! Added some minor comments

[gbamparop]

@LucaWintergerst can you please have a look? The last part encourages users to follow the logs-*-* naming pattern. Should we also mention Streams as the new way to ingest data and point to the documentation?

[LucaWintergerst]

@gbamparop let's make note of this somewhere and follow up, but I would not change anything at this time - we'll first need to ship 9.2 and we'll also need more coherent docs for Streams at this time with updates to the new UX changes.

[mdbirnstiehl]

Looks good with the updates! Thanks again!

[gbamparop]

@gbamparop let's make note of this somewhere and follow up, but I would not change anything at this time - we'll first need to ship 9.2 and we'll also need more coherent docs for Streams at this time with updates to the new UX changes.

cc @mdbirnstiehl so we can capture it for the future

[gbamparop]

Thank you!

[mdbirnstiehl]

@gbamparop let's make note of this somewhere and follow up, but I would not change anything at this time - we'll first need to ship 9.2 and we'll also need more coherent docs for Streams at this time with updates to the new UX changes.

cc @mdbirnstiehl so we can capture it for the future

I'll make a note, I assume we will have quite a bit of Streams docs planning coming up for 9.2.