Extend documentation for Security Orchestration Policy with Schedule Rules

Why are we doing this work

To support scheduled scans configured in Security Orchestration Policies we need to update the documentation.

Relevant links

• Epic

Non-functional requirements

• Documentation
• [-] Feature flag:
• [-] Performance:
• [-] Testing:

Implementation plan

• documentation extend doc/user/application_security/policies/index.md documentation with schedule rule type schema and example that explains how to use it,