Save the data about technikum and vocational schools

[annkamsk]

This would be a second step in resolving #15. The spreadsheet includes lots of data on technikum and vocational (szkoła branżowa) classes, which we didn't have in our model so far.

The task is to:

• Read the data from the spreadsheet (similarly to Update the data about high schools (pl: liceum) #16)
• Create new models of TechnikumClass and VocationalClass
• Put the new data to the database (remembering again that some information is already there)