Dockerize server

[bartolomej]

Context

I had issues with running this server because of the global node binary that Claude client app picked up.

Some example errors I got:

[MCP Server Error] ReferenceError: AbortController is not defined
    at Server._onrequest 

...

file:///Users/bartkozorog/.npm/_npx/38579/lib/node_modules/@ahrefs/mcp/build/server.js:5310
        const status = axiosError.response?.status;
                                           ^
SyntaxError: Unexpected token '.'

Description

It was way easier to just run the server within docker, so I did that. Submitting this here in case you think it's useful for other users as well.