Gestion questions/réponses

Closes #6 et #7

See merge request !7

In update and show routes

Page was slown down because of this.

The styles of the messages will be specified by type of message :
- error
- success
- log (dev)
- info

The list is fully extensible, just have to write style
for class msg-TYPE and call flash with the given type.

Page détails annonce

Closes #16

See merge request !6

Permission integration to ads pages/routes

Closes #15

See merge request !5

# Conflicts:
#   routes/ads.js

Only render a page section if the logged user is authorized to

Reinforce middleware, and add a function
which authorizes for a given user and required level.

Middleware that passes the session's user to all templates
with the name `_user`

Pictures support

Closes #11

See merge request !4

Ads en général en fait

Closes #1, #2, #4 et #5

See merge request !1

FOR DEVS I strongly advise you turn "fix on save" param for eslint on vscode