Create print_documents.md

Created a "How to print" documentation for EPITA students in Villejuif. This file needs to be completed with the KB procedure.

docs/print_documents.md

+# Print documents
+
+EPITA students are able to print documents with a dedicated web interface.
+
+## Villejuif
+
+In Villejuif, there are two printers available for students. You can access those printers from any web browser with two IP adresses:
+- 10.3.8.1
+- 10.3.8.2
+
+The first page provides informations related to the printer you want to print from, such as:
+- State
+- Ink porcentage
+- Sheets quantity
+
+You need to go in the *print* section to submit your documents.
+
+> Be aware that only *.ps*, *.pdf*, *.prn* or *.rfu* files are accepted. 
+
+## Kremlin-Bicêtre
+
+//TODO