Extend _type_map with Array

[bonedi]

I have some tables containing Array columns in a database. When DremioDialect.get_columns() is called ctype = _type_map[col[1]] throws an KEYERROR 'ARRAY'.
This can be solved with extending _type_map in base.py and query.py with:

_type_map = {
     ...
    'ARRAY': types.ARRAY,
    'array': types.ARRAY,
}

[villebro]

I also ran into this today. @narendrans if it's ok I'll open a PR to get this fix in