[FIX] websiste: determinist homepage for portal users

In the portal module,
the `index` method from the `web` module controllers
is overriden to redirect `/`
to the portal `/my` for the portal users,
instead of the regular backend `/web`.

However, when `website` is installed,
this behavior should not happen,
as you would like the signed in portal users to
be able to see the website homepage,
and not to be redirected to `my` when
they try to access `/` root path of the website.

Because the override in the website module was done on the
`index` method coming from the `web` module instead of the `portal`,
according in which way the Python module were loaded,
it sometimes redirected to `/my`, sometimes it correctly
displayed the homepage. This is because the modules are not
loaded in a determinist order.

To summarize, on runbot, if you logged as portal/portal,
one time on two you were redirected to `/my`, and the other
time you saw the homepage correctly.

As `website` depends on `portal`,
we have the possibility to override the `index` method
of `portal` instead of the one of `web`,
to force the determinist order,
and therefore the determinist behavior of the homepage for
portal users.

addons/website/controllers/main.py

@@ -18,8 +18,9 @@ from odoo import http, models, fields, _
 from odoo.http import request
 from odoo.tools import pycompat, OrderedSet
 from odoo.addons.http_routing.models.ir_http import slug, _guess_mimetype
-from odoo.addons.web.controllers.main import WebClient, Binary, Home
+from odoo.addons.web.controllers.main import WebClient, Binary
 from odoo.addons.portal.controllers.portal import pager as portal_pager
+from odoo.addons.portal.controllers.web import Home
 
 logger = logging.getLogger(__name__)