[hatohol-config-db-creator] Remove a command hatohol-db-creator.

Now we can register monitoring servers by WebUI.
So we don't need it. To reduce setup procedures and maintenace cost,
we decided to remove it.
[hatohol-config-db-creator] Remove descriptions for hatohol-config-db-creator.
[create-db.sql] Prepare an SQL command file for setup.
[doc] Brush up explaination.
[doc] Brush up the explaination again.
[TravisCI] Use the new set up way of the database.
[DBClientUser] Create initial users: admin/guest.

Previously these users are created by hatohol-config-db-creator.
It's hard to create them by SQL command file because tables are
created by Hatohol server automatically if needed. So we cannot
execute insert statements for adding users before Hatohol server
is executed once.

So this patch create them soon after the user table is created
in the Hatohol server.
[DBClientUser] Use a readable method name.
Merge pull request #337 from project-hatohol/issue-334

These patches remove hatohol-config-db-creator to simply the setup procedure of Hatohol server.