review SQL data types

[ChristinaLK]

Make the table of data types MUCH shorter + sqlite specific and add links to a full sqlite definition and other standards.

[nsoranzo]

Some comments/ideas:

• DB Browser for SQLite allows only INTEGER, TEXT, BLOB, REAL and NUMERIC, so I'd just reduce the first "Data types" table to these 5.
• Covering all data types listed in e.g. the SQL:2016 standard is too long and quite likely out of scope for this lesson
• The seconda table could be renamed to "SQL data types in different servers" and replace the "Access" column with SQLite.

[ChristinaLK]

@nsoranzo that first suggestion is exactly what we're looking for!