Minimal changes to Abschluss exercise.

• Updated dump_table_ddl stored function to being able to correctly print primary and foreign key constraints.

Prepared index exercises

Improved Q21/Q22/Q26 question text

Synchronized execqueries.sh scripts between different exercises.

• added timestamp when log file was generated

Updates to geometries table of exercise 1 of Datastructures exercises

Updated Triggers exercise

• finer grained steps to come to a solution

Updated exercises up to week 3

Reduced text duplications using attributes and includes

Prepared Final exercise and applied corrections and updates to solutions.

Updated postgraphile online instance URLs