Add default /docs route to list information about the SSE MCP server

[mconflitti-pbc]

Is your feature request related to a problem? Please describe.
Would be useful to have an equivalent to something like how FastAPI generates OpenAPI docs and are automatically accessible at /docs route.

Describe the solution you'd like
Add a /docs route to the starlette app that provides information about the mcp server (available tools, prompts, resources, version, etc.)

Describe alternatives you've considered
none

Additional context
Basic example I currently use: