update bootstrap, jquery, ui cleanup, improve ci

.gitlab-ci.yml

.pylintrc

Makefile

README.md

management/authentication.py

management/forms.py

management/management/commands/create_admin.py

management/models.py

management/static/management/css/style.css

management/templates/management/add_election.html

management/templates/management/add_session.html

management/templates/management/base.html

management/templates/management/index.html

management/templates/management/session.html

management/templates/management/session_settings.html

management/urls.py

management/utils.py

management/views.py

requirements_dev.txt

static/bootstrap-4.4.1-dist/css/bootstrap-grid.css.map