Assign correct INTEGER datatypes to sqlgen.go

[surister]

In sqlgen.go we assign Estuary data types, to CrateDB data types.

sql.STRING_INTEGER is typically used for very large integers, it should be changed to NUMERIC(30), choosing 30 arbitrarily, since picking the largest possible feels like a memory waste when it most likely won't be seen. If needed we can change it in the future if someone faces it as an issue.

[surister]

We cannot insert 18446744073709551615 (u64) with our current setup, due to schema mismatch, the recommendation of using sql.MapSignedInt64 as

sql.INTEGER: sql.MapSignedInt64(
   			sql.MapStatic("BIGINT", sql.AlsoCompatibleWith("integer"), sql.AlsoCompatibleWith("numeric")),
   			sql.MapStatic("NUMERIC(24)", sql.AlsoCompatibleWith("double precision")),
),

Does not work when getting NUMERIC sized integers as the column is firstly created as BIGINT.

[surister]

Found that we cannot insert integers bigger than BIGINT in objects(dynamic), something that we test/do in Estuary crate/crate#17669

[surister]

It seems that the issue is in sql.MapSignedInt64, the test data has maximum, so the NUMERIC should be used, but instead BIGINT is being used, we have to investigate why is the maximum parameter not being taken into account