[mcp] integrate a preference to enable/disable the embedded MCP server #1621
Description
We should integrate a preference to enable/disable the embedded MCP server. This might not be as straight forward as its sounds, since the embedded MCP server uses the embedded Spring Boot HTTP server functionality, which we then need to enable/disable from the outside (maybe via properties).
If the user disables the embedded MCP server, there should be no HTTP server being started by the language server at all.