[CloudSecurity][Docs] Streamlined CNCF Falco ingestion documentation

[nick-alayil]

Description

Background

https://github.com/elastic/security-team/issues/9873
https://github.com/elastic/security-team/issues/9980
https://github.com/elastic/security-team/issues/10379

Documentation Content

Detailed technical setup has been captured here.

Background & resources

• PRs:
• Issues/metas:
• Point of contact: @nick-alayil
• Test environments:

Which documentation set does this change impact?

ESS only

ESS release

8.16

Serverless release

N/A

Feature differences

N/A

API docs impact

N/A

Prerequisites, privileges, feature flags

N/A

[benironside]

complete in #6027