Initial checkin of geoscrub install SQL files.

Added install.*.sql files that will do initial table creation for all
required tables.
Added a truncate.vegbien_geoscrub.sql script that will clear tables related to
data downloaded in load-geoscrub-input.sh.
Moved all SQL statements that modify the final geoscrub table into the
geovalidate.sql script.
Modified the geonames.sql and geovalidate.sql scripts to assume all
tables have already been created by the install scripts.