User Guide update - Database Forge

Made section levels consistent with the other database reference docs.
Added return value writeups.
Signed-off-by:James L Parry <jim_parry@bcit.ca>
User Guide update - Datbase Utilities

1) Updated TOC structure of the DB Utilities writeup
2) Added a class reference at the end, ordered by method name
Signed-off-by:James L Parry <jim_parry@bcit.ca>
User Guide update - Datbase Utilities

1) Updated TOC structure of the DB Utilities writeup
2) Added a class reference at the end, ordered by method name
Signed-off-by:James L Parry <jim_parry@bcit.ca>
User Guide update - Datbase Utilities

Fixed the return types
Signed-off-by:James L Parry <jim_parry@bcit.ca>
Fix the user guide writeup for the DB forge
Signed-off-by:James L Parry <jim_parry@bcit.ca>
Merge pull request #3375 from jim-parry/userguide/dbforge

User Guide update - Database Forge
Merge branch 'develop' of github.com:bcit-ci/CodeIgniter into userguide/database_utilities
Merge pull request #3378 from jim-parry/userguide/database_utilities

User Guide update - Database Utilities