Adds applies tags to Troubleshoot > Observability section (#705)

- Adds applies tags to Troubleshoot > Observability section.
- Deletes `troubleshoot/observability/apm/known-issues.md`, since that
content already exists in the [release
notes](https://docs-v3-preview.elastic.dev/elastic/docs-content/tree/main/release-notes/known-issues/apm).

Preview:
[Observability](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/705/troubleshoot/observability)

---------

Co-authored-by: Colleen McGinnis <[email protected]>
Co-authored-by: Brandon Morelli <[email protected]>

Author: 3 people

solutions/observability/apps/apm-agent-compatibility.md

@@ -44,7 +44,7 @@ The chart below outlines the compatibility between different versions of Elastic
 | `1.x` | ≥ `6.5` |
 
 ::::{note} 
-Java agent < 1.43.0 not fully compatible with APM Server >= 8.11.0. Read more in [Known issues](../../../troubleshoot/observability/apm/known-issues.md#apm-empty-metricset-values).
+Java agent < 1.43.0 not fully compatible with APM Server >= 8.11.0. Read more in [Known issues](/release-notes/known-issues/elastic-apm.md).
 
 ::::
 

troubleshoot/observability.md

@@ -2,6 +2,10 @@
 navigation_title: "Observability"
 mapped_pages:
   - https://www.elastic.co/guide/en/observability/current/troubleshooting.html
+applies_to:
+  stack: all
+  serverless:
+    observability: all
 ---
 
 # Troubleshoot Observability [troubleshooting]

troubleshoot/observability/amazon-data-firehose.md

@@ -2,6 +2,10 @@
 navigation_title: "Amazon Data Firehose"
 mapped_pages:
   - https://www.elastic.co/guide/en/observability/current/monitor-aws-firehose-troubleshooting.html
+applies_to:
+  stack: all
+  serverless:
+    observability: all
 ---
 
 

troubleshoot/observability/apm-agent-dotnet/apm-net-agent.md

@@ -2,6 +2,10 @@
 navigation_title: "APM .NET agent"
 mapped_pages:
   - https://www.elastic.co/guide/en/apm/agent/dotnet/current/troubleshooting.html
+applies_to:
+  stack: all
+  serverless:
+    observability: all
 ---
 
 # Troubleshoot APM .NET agent

troubleshoot/observability/apm-agent-go/apm-go-agent.md

@@ -2,6 +2,10 @@
 navigation_title: "APM Go Agent"
 mapped_pages:
   - https://www.elastic.co/guide/en/apm/agent/go/current/troubleshooting.html
+applies_to:
+  stack: all
+  serverless:
+    observability: all
 ---
 
 # Troubleshoot APM Go Agent

troubleshoot/observability/apm-agent-java/apm-java-agent.md

@@ -2,6 +2,10 @@
 navigation_title: "APM Java Agent"
 mapped_pages:
   - https://www.elastic.co/guide/en/apm/agent/java/current/trouble-shooting.html
+applies_to:
+  stack: all
+  serverless:
+    observability: all
 ---
 
 # Troubleshoot APM Java Agent [trouble-shooting]

troubleshoot/observability/apm-agent-nodejs/apm-nodejs-agent.md

@@ -2,6 +2,10 @@
 navigation_title: "APM Node.js Agent"
 mapped_pages:
   - https://www.elastic.co/guide/en/apm/agent/nodejs/current/troubleshooting.html
+applies_to:
+  stack: all
+  serverless:
+    observability: all
 ---
 
 # Troubleshoot APM Node.js Agent [troubleshooting]

troubleshoot/observability/apm-agent-php/apm-php-agent.md

@@ -2,6 +2,10 @@
 navigation_title: "APM PHP Agent"
 mapped_pages:
   - https://www.elastic.co/guide/en/apm/agent/php/current/troubleshooting.html
+applies_to:
+  stack: all
+  serverless:
+    observability: all
 ---
 
 # Troubleshoot APM PHP Agent [troubleshooting]

troubleshoot/observability/apm-agent-python/apm-python-agent.md

@@ -2,6 +2,10 @@
 navigation_title: "APM Python Agent"
 mapped_pages:
   - https://www.elastic.co/guide/en/apm/agent/python/current/troubleshooting.html
+applies_to:
+  stack: all
+  serverless:
+    observability: all
 ---
 
 # Troubleshoot APM Python Agent [troubleshooting]

troubleshoot/observability/apm-agent-ruby/apm-ruby-agent.md

@@ -2,6 +2,10 @@
 navigation_title: "APM Ruby Agent"
 mapped_pages:
   - https://www.elastic.co/guide/en/apm/agent/ruby/current/debugging.html
+applies_to:
+  stack: all
+  serverless:
+    observability: all
 ---
 
 # Troubleshoot APM Ruby Agent [debugging]