erp5_search_rank_catalog: do not destroy the previously calculated rank

erp5_search_rank_catalog: Show module content before tools content

erp5_search_rank_catalog: keep default value low, to prevent having huge rank score

Otherwise, method draw enter an infinite loop if users selected some elements

https://github.com/methodofaction/Method-Draw/tree/463e526dbc6ec48561822fde5dec02e085e86497

Lazy loading img are also not loaded, which speed up page rendering.

This should evolve to become a browser-side OAuth2 client.

So every new instance is able to use self-contained oauh2 authentication.
In turn, this triggers atomated migration of a few portal types, which
cause the coding style tests to fail. So commit these as well.

Replace CookieCrumbler's cookie with OAuth2 tokens:
- add the notion of authenticated sessions: period from a login action to
  either a logout or the expiration of tokens
- avoids session fixation (knowing one token does not grant near-permanent
  access to the session)
- reduces the per-request cost of authentication (removes the need to
  compute user's groups, and the need to cache these groups for a fixed
  period).

Also, to reliably open login_form, log out.

This is a simplified version that works well enough for python 2.
For Zope 4 and python 3 we are considering reusing publish.