Return ability to use custom loggers and to set loggers for a specific route

[Satbek]

In v1.1.0 was ability to set custom request and error loggers for whole server and specific route.
It is pr where this feature was provided #77 .

In v2.0.1 this ability was lost. Let's return it.

Changes:

• http.server.new also can accept log_requests, log_errors as function values
• add log_requests, log_errors options to router:route options.
  They override the server parameter of the same name, but only for current route.