So that we can stop using Tim's photo for tests, adds an open
license profile picture to use instead.
Updates tests that used `tim.png` to use the new example profile
picture, which is located in `static/images/test-images/avatars/`.
Changed the name of the test-user cordelia from `Cordelia Lear` to
`Cordelia, Lear's daughter`.
This change will enable us to test users with escape characters in
their names.
I also updated the Node, Puppeteer, Backend tests and Fixtures to
support this change.
To avoid some hidden bugs in tests caused by every ldap user having the
same password, we give each user a different password, generated based
on their uids (to avoid some ugly hard-coding in a bunch of places).
Simon Michalke
Lauryn Menard
Alya Abbott
Arun Sankar
Mateusz Mandera