Update populate_database.sh for Icehouse

1. Added comments
2. Asks the root password and execute based on the input password
3. Added Heat & Trove
4. Improved readability
Update keystone_basic.sh

1. Edited basic comments
2. Input several parameters using 'read' functionality
3. Created user for neutron, cinder & heat
Update keystone_endpoints_basic.sh

1. Added comments for usage
2. Creates neutron & heat endpoints
Update populate_database.sh

MySQL comment requires at least 'one whitespace' after --
Update populate_database.sh

Added 'successfully created'
Update populate_database.sh

Changed: % -> localhost