[8.x] Updates "Cloud native security" to "Cloud security" (backport #6175) (#6251)

* Updates "Cloud native security" to "Cloud security" (#6175)

* Updates "Cloud native security" to "Cloud security"

* incorporates Smriti's and Nick's reviews

* Capitalizes S in Security

(cherry picked from commit 863c54f)

# Conflicts:
#	docs/serverless/cloud-native-security/cloud-native-security-overview.asciidoc
#	docs/serverless/security-overview.asciidoc

* Delete docs/serverless directory and its contents

---------

Co-authored-by: Benjamin Ironside Goldstein <[email protected]>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

Author: 3 people

docs/cloud-native-security/cloud-native-security-index.asciidoc

@@ -1,5 +1,5 @@
 [[cloud-native-security-overview]]
-= Cloud native security
+= Cloud Security
 Elastic Security for Cloud helps you improve your cloud security posture by comparing your cloud configuration to best practices, and scanning for vulnerabilities. It also helps you monitor and investigate your cloud workloads inside and outside Kubernetes.
 
 This page describes what each solution does and provides links to more information.

docs/es-overview.asciidoc

@@ -18,7 +18,7 @@
 * <<getting-started, Get started>>: Learn about system requirements, workspaces, configuration, and data ingestion.
 * <<es-ui-overview, {elastic-sec} UI overview>>: Navigate {elastic-sec}'s various tools and interfaces.
 * <<about-rules, Detection rules>>: Use {elastic-sec}'s detection engine with custom and prebuilt rules.
-* <<cloud-native-security-overview, Cloud native security>>: Enable cloud native security capabilities such as Cloud and Kubernetes security posture management, cloud native vulnerability management, and cloud workload protection for Kubernetes and VMs.
+* <<cloud-native-security-overview, Cloud security>>: Enable cloud native security capabilities such as Cloud and Kubernetes security posture management, cloud native vulnerability management, and cloud workload protection for Kubernetes and VMs.
 * <<install-endpoint, Install {elastic-defend}>>: Enable key endpoint protection capabilities like event collection and malicious activity prevention.
 * https://www.elastic.co/products/stack/machine-learning[{ml-cap}]: Enable built-in {ml} tools to help you identify malicious behavior.
 * <<advanced-entity-analytics-overview, Advanced entity analytics>>: Leverage {elastic-sec}'s detection engine and {ml} capabilities to generate comprehensive risk analytics for hosts and users.