Merge branch 'fix/sqlite3TreeCircle' into 'ver/5.17.x'

SQLite3 database: prevent self-circling of 'tree' mixin in case of parentID...

See merge request !83 (merged)

(cherry picked from commit f5f83baa)

0ba67811 SQLite3 database: prevent self-circling of 'tree' mixin in case of parentID...