make initServer and serve macros

[Ethosa]

Simple syntax:

initServer:
  var server = newServer()
  server.routes:
    "/":
      req.answer "Hi"
  server.start()

serve("127.0.0.1", 5000):
  "/":
    req.answer "Hi"

It's will be nice shortcut for

proc main() =
  var server = newServer()
  server.routes:
    "/":
      req.answer "Hi"
  server.start()
main()