Change Map support to use Array[Row]

[jeremyprime]

Is your feature request related to a problem? Please describe.

Vertica does not support the Map complex type directly, only through external tables.

Describe the solution you'd like

Vertica does support Array[Row], so the Spark Connector could use Array[Row] in place of Map against Vertica tables (internal and external).

Will want to first investigate to see if there are any issues with using Array[Row] in place of Map and ensure the Spark Map type is compatible. Not sure if this functionality was available when we first added complex types support and there was another reason why we did not use Array[Row] in place of Map, or if it was added to a more recent version of Vertica.