Load times on list view pages like Slices, Dashboards, Tables and Database
have grown to be terrible over time.
After a bit of digging, I found that the not specifying `search_columns`
in ModelViews actually means "all columns" and that for each filter,
FAB goes and fetches a list of all values to prepopulate the
filter dropdowns. That means that the list of tables would fetch all
slices and all users upfront which is horrible. Worse, database list
view would fetch all queries with is insane.
This picks a subset of columns for search/filters and changes the
default to show only 100 elements per page instead of 500
