cubicweb #3955093 req.base_url() may not always have a trailing '/' [validation pending]

Especially when read directly from base-url or https-url. This causes problems all over CubicWeb. Here's a snippet from cubicweb.ajax.js:

var AJAX_PREFIX_URL = 'ajax';
var JSON_BASE_URL = BASE_URL + 'json?';
var AJAX_BASE_URL = BASE_URL + AJAX_PREFIX_URL + '?';

And there are dozens more places where BASE_URL, baseuri() or req.base_url() is used under the assumption that the returned URL has a trailing /.

prioritynormal
typebug
done in3.20.0
load0.500
load left0.000
closed by#e3d2012adcd0 [request] Ensure base_url() always has a trailing '/' (closes #3955093)
patch[request] Ensure base_url() always has a trailing '/' (closes #3955093) [applied]