Remove authenticate as check_credentials is dedicated for this
purpose.
Removed mail translations maybe possible in some way ?
Give some space to the code
Make the addon compliant to OCA guidelines
Adapt readme to new template and compress header in tests
Make the addon a python package
NOTE: authenticate() method cannot be used in tests because a new cr
is created in _login method that does not contains our user.
Signed-off-by: Eugen Don <eugen.don@don-systems.de>