Update practicals

[johnsamuelwrites]

Update practicals:

1. Combine practicals 0 and 1
2. Remove images of the output of code from practicals 1, 2 and 3
3. Add example on other available classifiers (AdaBoost, nearest neighbours,..)
4. Update project description to evaluate multiple classifiers or clustering algorithms

[johnsamuelwrites]

Combine practicals 0 and 1

Currently, practicals 0 is marked optional and linked with practicals 1 for students who wish to recall Python programming.

2. Remove images of the output of code from practicals 1, 2 and 3

Updated practicals 1 to precise that the screenshots are there for comparing the obtained results and the desired results.