Copy code of canonical-base implementation to c.c.algorithms

To optimize it there

Signed-off-by: Daniel Borchmann <daniel.borchmann@mailbox.tu-dresden.de>
Removed test-cases for parallel-canonical-base

Signed-off-by: Daniel Borchmann <daniel.borchmann@mailbox.tu-dresden.de>
Adjusting tests for conexp.contrib.algorithms

Signed-off-by: Daniel Borchmann <daniel.borchmann@mailbox.tu-dresden.de>