Replace FLOAT types with NUMERIC

[miike]

By replacing some of the current transaction FLOAT types with NUMERIC we avoid any floating point arithmetic issues that we can run into if using BigQuerys FLOAT64.

[chuwy]

8653b16

[dilyand]

@chuwy Can this be closed?

[chuwy]

No, I think we still need this change. BQ Loader is shipped with schema-ddl 0.9.0 since 0.2.0, which means it creates new columns with NUMERIC type snowplow/iglu#426. Now we need to cherry-pick 8653b16 to reflect this standard atomic events fields.