populate form with settings, general admin form improvements

[bradfordcondon]

• Now that we store previous run in a table, we should populate the form with existing settings
• User should be warned that submitting truncates the index table and re-indexes
• User should be informed that adding new entities doesnt mean they ahve to re-index because entities are added via hook

other stuff?

[bradfordcondon]

Note: There is a bigger goal, which would be :

• User should be able to add a new configuration without rebuilding hte index.
• User should be able to manage CV/bundle combination.s
  • for example, i should bea ble to index GO for mrna, but not GO for biomaterials.

[almasaeed2010]

It's hard not to truncate since we don't have foreign keys points towards chado cv terms. What if they are reindexing because the term has been deleted? Or the relationships were updated for some reason?