Recent version of tzlocal v5 is not compatible with cherrypy

- Handle case when repo is damaged.
- Replace bootstrap-email by jinja2 templates
- Change layout of report
- Fix date format timezone
- Fix new, delete, change values

- Support multiple ldap-required-group
- Add support for LDAP group filtering
- Improve LDAP documentation

* Make use of session variable to redirect user during login
* Centralize management of login into `auth_form` tool
* Create a new module `auth_mfa` to handle email authentication

* Remove Debian Stretch build
* Drop support of jinja2<2.10
* Drop support of cherrypy<8.9.1

The pipeline is failing very often because of network issue. To reduce
failure and reduce the download time, let point pip to our pip-proxy.

To avoid regression based on Jinja version add it to Tox environment
list. Also add job for them in gitlab pipeline

We need to use latest pip version to pick the right version of pacakges
for py27. Otherwise, pip will install python 3 only packages into a
python 2.7 environment.