Feat (ContentTemplates) - Add asset.model, asset.state and user.registration_number variables

[RomainLvr]

Checklist before requesting a review

Please delete options that are not relevant.

• I have read the CONTRIBUTING document.
• I have performed a self-review of my code.
• I have added tests that prove my fix is effective or that my feature works.
• This change requires a documentation update.

Description

• It fixes !39546
• Here is a brief description of what this PR does

Add new Twig variables for content templates

This PR introduces three new template variables to enhance content template capabilities:

Asset variables:

• {{ asset.model }} - Returns the asset's model name (e.g., "Dell OptiPlex")
• {{ asset.state }} - Returns the asset's current state (e.g., "In service", "Broken")

User variable:

• {{ user.registration_number }} - Returns the user's administrative/employee number

Changes:

• Updated AssetParameters.php to fetch model via getModelClass() and state via State class
• Updated UserParameters.php to include registration number from user fields
• Added comprehensive test coverage for all new variables
• Updated existing tests to handle new user parameter in ITIL objects

Screenshots (if appropriate):