Bug 13669: Use perl to load SQL statements from sample data

Bug 13669: Use perl to load SQL statements from sample data

This patch changes C4::Installer::load_sql so it uses File::Slurp [1] to read
the SQL files, and SQL::SplitStatement to extract the statements from the full SQL
file so they can be passed to $dbh->do.

To test:
- On Mysql 5.5, run the webinstaller
=> SUCCESS: Everything works as expected
- Apply the patch
- Run
  $ mysql -uroot
  > DROP DATABASE koha_kohadev ; CREATE DATABASE koha_kohadev;
- Run the webinstaller
=> SUCCESS: Everything works as expected
- On Mysql 5.6+ (5.7 is implied)
- Run
  $ mysql -uroot
  > DROP DATABASE koha_kohadev ; CREATE DATABASE koha_kohadev;
- Run the webinstaller
=> FAIL: It cannot load the sql files due to a password-in-command-line error
- Apply the patch
- Make sure everything is clean (it should):
  $ mysql -uroot
  > DROP DATABASE koha_kohadev ; CREATE DATABASE koha_kohadev;
- Run the webinstaller
=> SUCCESS: EVerything works as expected
- Sign off :-D

[1] Note: This is a POC patch, in the sense that it does the job, fixes a nasty problem
but using File::Slurp to load the SQL files in memory comes with a big runtime penalty.
You will notice the install procedure is now much slower, for instance.

Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>