RUN-643: Multiline job options beta documentation

[gschueler]

No description provided.

[Copilot]

Pull Request Overview

This PR adds documentation for a new beta feature in Rundeck - Multiline Text job options. The documentation explains how to configure and use multiline text inputs for job options, which is a new option type alongside the existing text and file types.

Key changes:

• Restructures the job options documentation to organize content by option types
• Adds comprehensive documentation for the new Multiline Text option type (beta feature since v5.17.0)
• Improves the organization and clarity of existing option configuration sections

[Copilot]

The beta feature callout is missing proper formatting and explanation. Consider adding more context about what this feature enables and any limitations or considerations for beta usage.

Suggested change

	:::betafeature Beta Feature (Since v5.17.0)
	To enable this feature, add the config `rundeck.feature.multilineJobOptions.enabled=true`
	:::
	> **Beta Feature: Multiline Text Option (Since v5.17.0)**
	>
	> The "Multiline Text" option type allows users to enter multi-line input when running a job, making it easier to provide longer or formatted text values.
	>
	> **How to enable:**
	> This feature is currently in beta and is disabled by default. To enable it, add the following configuration to your `rundeck-config.properties` file:
	> ```
	> rundeck.feature.multilineJobOptions.enabled=true
	> ```
	>
	> **Limitations and considerations:**
	> - As a beta feature, functionality and behavior may change in future releases.
	> - Some plugins or integrations may not fully support multi-line option values.
	> - When using regular expressions for validation, ensure you use the `(?s)` flag to match across multiple lines (see "Restrictions" below).
	> - Please test thoroughly before using in production environments.