TAP_SCHEMA.columns datatype for arraysize

[mdgomes]

The current Proposed Recommendation for TAP_SCHEMA columns "arraysize" has the datatype as string instead of integer (as on the original working drafts).

The arraysize column gives the length of fixed and variable length datatypes using the VOTable array shape syntax. For example, a database column of type varchar(256) would be described with datatype "char" and arraysize "256*". Arrays, including multi-dimensional arrays, are permitted for all VOTable primitive types. The "size" column is retained for backwards compatibility to TAP-1.0 and must contain the integer value equivalent to arraysize when possible and must be null if arraysize is null or represents a multi-dimensional array. Both arraysize and "size" must be null for scalar numeric columns.

From: PR-TAP-1.1-20180416

This would mean changing the corresponding DBDataType in TAPMetadata.java.