use with_recursive for faster access on rails >= 7.2

[patriciomacadden]

Rails >= 7.2 added #with_recursive, which allows us to write CTE (Common Table Expressions) in postgresql, sqlite and mysql.

The bigger the tree gets, the slower is traversing it with the current implementation. This PR allows to fetch the whole tree in just 1 query by using #with_recursive.

Also, added newer versions of ruby and rails to the ci matrix

[felixbuenemann]

• What happens if the underlying database does not support recursive queries (eg. MySQL < 8)?
• The code uses raw sql without proper quoting
• Is it really necessary to duplicate so many methods with recursive and non-recusrive version ir can they share more code?