Mp/attempt to patch snowflake types

[VersusFacit]

resolves #310
docs issue

Problem

If a given column is a complex ARRAY type such as ARRAY(VARCHAR(16777216)), the macro get_columns_in_relation raises an error.

In the SnowflakeColumn class, we're restricting things artificially by trying to parsing this among other simple types as a LABEL(NUMERIC) type.

Solution

Structured types are more generic and require overrides not to go through this parsing song and dance.

We can override at the Snowflake level to avoid disruption the Base Adapter and other adapters which have different type names.

Alternative Considered

I thought about doing more sophisticated parsing here into these types' subtypes. But, this presents a major problem. In particular, we'd be building a Snowflake compliant AST for not much value to the user. Instead, we trust users to employ these types in their columns and that Snowflake will flag any subtyping problems in an intelligent way.

Checklist

• I have read the contributing guide and understand what's expected of me
• I have run this code in development and it appears to resolve the stated issue
• This PR includes tests, or tests are not required/relevant for this PR
• This PR has no interface changes (e.g. macros, cli, logs, json artifacts, config files, adapter interface, etc) or this PR has already received feedback and approval from Product or DX