Bug 17855 - Reverted back to original step 3 in the web installer so there is no...

Bug 17855 - Reverted back to original step 3 in the web installer so there is no basic and advanced setup mode and consequently no need for SQL files to be moved to a 'default' directory for all languages.

Onboarding tool and the rest of the web installer still exists in this
commit

How I tested in my VM (Current master):
- Dropped database
- Recreated database
- Went through installer
- Language en, Marc21
- Installed mandatory data only
- Went through Onboarding tool
- After finishing, logged in as superlibrarian
  that was created by onboarding tool
Everything worked fine.

Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>