Basic HTTP servers (#2) and various improvements over docs.

server/internal/services/core/http/replies.go

@@ -0,0 +1,10 @@
+package http
+
+import (
+	"github.com/gin-gonic/gin"
+)
+
+func (h *http) ReplyJSON(ctx *gin.Context, statusCode int, data interface{}) {
+	ctx.Writer.Header().Add("Content-Type", "application/json")
+	ctx.JSON(statusCode, data)
+}