Replace string DB fields with more appropriate data types

[DerEwige]

For example you chose to store the UUIDs in text fields
Which make them use 36 byte instead of 16 byte if you would use the built in UUID data type
If you would revamp to use BIGINT where it is possible instead you would go down to 8 byte.

This would shrink the database (and the indexes in particularly) and make the whole DB a lot faster.