Initial experiments with importing the data set list into sqlite database.

Created table 'raw' which contains the data from the xls.
Extracted formats from the 'raw' table, and added mapping to existing rows in
the 'raw' table.
Normalization of data.

Dates changed so that they have only one format (YYYY-MM-DD).
Vyjadrenie and zverejnitelnost normalized into fewer values.
Clean up of the sqlite database.

Dropped not required tables, created views, and the dataset table.