feature: Leverage separate plugin framework and manager when available

[evaline-ju]

Feature Description

Work is in progress in this epic to decouple the plugin framework from the rest of ContextForge. Since the plugins-adapter leverages this manager for managing plugins, this should be updated and likely allow for slimmer dependencies.

Proposed Solution

• Incorporate package when available from [EPIC][PLUGIN]: Decouple plugin framework from mcpgateway dependencies IBM/mcp-context-forge#2575 and replace plugin manager instance
• Update documentation instances with information on the plugin manager e.g. https://github.com/kagenti/plugins-adapter/tree/main/docs/architecture#plugin-manager

Want to contribute?

• I would like to work on this issue.

Additional Context

No response