DOC-3408 - Clarify that both bundling and lazy loading are fully supported

[kemister85]

Ticket: DOC-3408

Site: Staging branch

Changes:

• Removed "(Recommended)" label from the bundling section heading on the plugins bundling page
• Rewrote the "Using premium plugins" intro to explicitly state both bundling and loading with external_plugins are fully supported and production-ready
• Reframed the external_plugins section as an equal option rather than a fallback, noting that Tiny Cloud uses the same mechanism
• Updated license-key.adoc to use neutral language for the external_plugins reference

Pre-checks:

• Branch is correctly prefixed:
• Build passes without console errors, warnings, or issues.

Review:

• Documentation Team Lead has reviewed.