feat: add customizable support and documentation URLs for enterprise

[akramcodez]

What does this PR do?

Enables enterprise customers to redirect support and documentation links to their own internal resources instead of the default Activepieces community.

Explain How the Feature Works

Two new environment variables can be configured:

• AP_SUPPORT_URL: Redirects all support links to a custom URL (e.g., internal helpdesk)
• AP_DOCS_URL: Redirects documentation links to custom docs (e.g., internal wiki)

If not set, links default to standard Activepieces URLs (fully backward compatible).

Affected locations:

• Builder header "Support" button
• Help & Feedback → "Documentation" link
• Help & Feedback → "Community Support" link

Relevant User Scenarios

1. Enterprise with internal support portal - Direct users to company's helpdesk/ticketing system
2. Regulated industries - Keep users within internal network, no external community access
3. Custom documentation - Point to company-specific guides and workflows
4. White-label deployments - Maintain consistent branding across all support touchpoints

Fixes #9413

[akramcodez]

PTAL @abuaboud, thanks.