Updating debugging docs: replacing apm.dev.js configuration references with kibana.dev.yml (#152237)

## Summary

Updating the Debugging Kibana documentation:

1. Adding Python as additional pre-requisite technology
2. Replacing apm.dev.js configuration with updated kibana.dev.yml
approach

Similar to recent discussion in issue #79490, I've found that the
`apm.dev.js` approach is no longer working.


### Checklist

Delete any items that are not applicable to this PR.

- [X]
[Documentation](https://www.elastic.co/guide/en/kibana/master/development-documentation.html)
was added for features that require explanation or tutorials

### Risk Matrix

N/A

### For maintainers

- [ ] This was checked for breaking API changes and was [labeled
appropriately](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)

docs/developer/getting-started/debugging.asciidoc

@@ -38,15 +38,15 @@ https://www.elastic.co/guide/en/apm/agent/nodejs/current/configuration.html#acti
 APM config option.
 
 All config options can be set by
-creating an appropriate config file under `config/apm.dev.js`. 
+creating an appropriate config file under `config/kibana.dev.yml`. 
 
-Example `config/apm.dev.js` file:
+Example `config/kibana.dev.yml` file:
 
-[source,js]
+[source,yaml]
 ----
-module.exports = {
-  active: true,
-};
+elastic:
+  apm:
+    active: true
 ----
 
 APM
@@ -68,7 +68,7 @@ UI in {kib}.
 [discrete]
 === Running Kibana with the APM Agent Locally
 
-The easiest and recommended way of running Kibana with the APM agent locally is to use the solution provided by the https://github.com/elastic/apm-integration-testing[apm-integration-testing] repo. You’ll need https://www.docker.com/community-edition[Docker] and https://docs.docker.com/compose/install/[Docker Compose] to use the tool.
+The easiest and recommended way of running Kibana with the APM agent locally is to use the solution provided by the https://github.com/elastic/apm-integration-testing[apm-integration-testing] repo. You’ll need https://www.docker.com/community-edition[Docker], https://docs.docker.com/compose/install/[Docker Compose] and https://www.python.org/downloads[Python (version 3 preferred)] to use the tool.
 
 [discrete]
 ==== Quick start guide
@@ -88,6 +88,7 @@ cd apm-integration-testing
 ./scripts/compose.py start master --no-kibana
 ----
 
+. Clone the https://github.com/elastic/kibana[elastic/kibana] repo.
 . Change into the {kib} repo:
 +
 [source,bash]
@@ -96,20 +97,20 @@ cd ../kibana
 ----
 
 . Change the elasticsearch credentials in your `kibana.yml` configuration file to match those needed by elasticsearch and the APM server (see the apm-integration-testing repo's https://github.com/elastic/apm-integration-testing#logging-in[README] for users provided to test different scenarios).
-. Make sure that the APM agent is active and points to the local APM server by adding the following configuration settings to a config file under `config/apm.dev.js`:
+. Make sure that the APM agent is active and points to the local APM server by adding the following configuration settings to a config file under `config/kibana.dev.yml`:
 +
-Example `config/apm.dev.js` file:
+Example `config/kibana.dev.yml` file:
 +
-[source,js]
+[source,yaml]
 ----
-module.exports = {
-  active: true,
-  serverUrl: 'http://127.0.0.1:8200', // supports `http://localhost:8200`
-  centralConfig: false,
-  breakdownMetrics: false,
-  transactionSampleRate: 0.1,
-  metricsInterval: '120s'
-};
+elastic:
+  apm:
+    active: true
+    serverUrl: http://localhost:8200
+    secretToken: very_secret
+    centralConfig: true
+    breakdownMetrics: true
+    transactionSampleRate: 0.1
 ----
 
 . Start Kibana with APM active using: