Increase cohesion between koa and koaJsonRpc

[georgi-l95]

Problem

Koa and KoaJsonRpc logic is separated in server, which makes for harder debugging, because of the increased coupling. With the rate limit we introduced custom json rpc, which can be combined with koa for increased cohesion.

Solution

Look for way to combine koa and jsonrpc in one class.

Alternatives

No response