Implemented self-signup

deps/ldapalchemy

tests/test_selfservice.py

tests/test_signup.py

tests/utils.py

uffd/__init__.py

uffd/default_config.cfg

uffd/sendmail.py

uffd/session/__init__.py

uffd/session/templates/login.html

uffd/session/views.py

uffd/signup/__init__.py

uffd/signup/models.py

uffd/signup/templates/signup/confirm.html

uffd/signup/templates/signup/mail.txt

uffd/signup/templates/signup/start.html

uffd/signup/templates/signup/submitted.html

uffd/signup/views.py

uffd/user/models.py