[Infra and hosts] Add info on supported data sources for Infra Inventory

[mdbirnstiehl]

This PR closes #4077 and #4076 and updates the Infrastructure UI and metrics reference docs to show that only data from supported integrations can be used in the Infrastructure UI.

• Adds links to reference docs from the Infra UI docs.
• Updates reference docs to show supported integrations
• Updates reference docs to show filter logic for us

[github-actions]

Vale Linting Results

Summary: 13 suggestions found

💡 Suggestions (13)

File	Line	Rule	Message
reference/observability/observability-aws-metrics.md	62	Elastic.Acronyms	'SQS' has no definition.
reference/observability/observability-aws-metrics.md	80	Elastic.Acronyms	'RDS' has no definition.
reference/observability/observability-aws-metrics.md	98	Elastic.FutureTense	'will not' might be in future tense. Write in the present tense to describe the state of the product as it is now.
reference/observability/observability-aws-metrics.md	100	Elastic.Acronyms	'RDS' has no definition.
reference/observability/observability-aws-metrics.md	100	Elastic.Acronyms	'SQS' has no definition.
reference/observability/observability-aws-metrics.md	101	Elastic.Acronyms	'RDS' has no definition.
reference/observability/observability-aws-metrics.md	101	Elastic.Acronyms	'SQS' has no definition.
reference/observability/observability-container-metrics.md	60	Elastic.Capitalization	'container metrics' should use sentence-style capitalization.
reference/observability/observability-container-metrics.md	88	Elastic.FutureTense	'will not' might be in future tense. Write in the present tense to describe the state of the product as it is now.
reference/observability/observability-host-metrics.md	185	Elastic.FutureTense	'will not' might be in future tense. Write in the present tense to describe the state of the product as it is now.
reference/observability/observability-kubernetes-pod-metrics.md	13	Elastic.Capitalization	'pod metrics' should use sentence-style capitalization.
reference/observability/observability-kubernetes-pod-metrics.md	30	Elastic.WordChoice	Consider using 'refer to (if it's a document), view (if it's a UI element)' instead of 'see', unless the term is in the UI.
reference/observability/observability-kubernetes-pod-metrics.md	37	Elastic.FutureTense	'will not' might be in future tense. Write in the present tense to describe the state of the product as it is now.

[github-actions]

🔍 Preview links for changed docs

• reference/observability/observability-aws-metrics.md
• reference/observability/observability-container-metrics.md
• reference/observability/observability-host-metrics.md
• reference/observability/observability-kubernetes-pod-metrics.md
• solutions/observability/incident-management/create-an-inventory-rule.md
• solutions/observability/infra-and-hosts/analyze-compare-hosts.md
• solutions/observability/infra-and-hosts/view-infrastructure-metrics-by-resource-type.md