[feature/performance] Wrap incoming HTTP requests in timeout handler (#2353)

* deinterface router, start messing about with deadlines

* weeeee

* thanks linter (thinter)

* write Connection: close when timing out requests

* update wording

* don't replace req

* don't bother with fancy Cause functions (I'll use them one day...)

internal/api/client.go

@@ -79,7 +79,7 @@ type Client struct {
 	user           *user.Module           // api/v1/user
 }
 
-func (c *Client) Route(r router.Router, m ...gin.HandlerFunc) {
+func (c *Client) Route(r *router.Router, m ...gin.HandlerFunc) {
 	// create a new group on the top level client 'api' prefix
 	apiGroup := r.AttachGroup("api")