[server] Move SQLUtils::getFullName() to DBAgent::TableProfile

`SQLUtils::getFullName(columnDefs, index)` finds `ColumnDef` at `index`
from `ColumnDefs` and generates name with table name.

In the current code base, `DBAgent::TableProfile` manages
`ColumnDefs`. So it is natural that the feature is provided by
`DBAgent::TableProfile`.

New method is `DBAgent::TableProfile::getFullColumnName(index)`.