[CX] Don't mention tinyint/smallint/integer/float types in DP3 documentation

http://docs.couchbase.com/prerelease/analytics-dp3/9_data_type.html

Let's not mention the following numeric types in the DP3 documentation:

TINYINT, SMALLINT, INTEGER, FLOAT. They cannot enter the system from JSON, and cannot be used in secondary indexes.

We should only document DOUBLE and BIGINT types