[FEATURE] Add OAuth support for the MCP server

[firecast]

[enkoder]

I'd like to add in addition to adding OAuth support, it would be ideal if Atlan shipped a first-party MCP server that supported OAuth as an official server. This is where the industry is going and makes it trivial for customers to configure and vastly improve the security posture of MCP servers in an enterprise environment. OAuth + First party APIs are becoming a must have for all modern saas tools. I'm sure it's already on the roadmap, but wanted to +1 how impactful it will be for us.