feat: adding a check_exclude_cols strategy

[willmaclean]

resolves #273
docs dbt-labs/docs.getdbt.com/#

Problem

A feature was proposed to have a check_exclude_colsconfig option on a snapshot in dbt-core, and this is the adapter implementation of it.

Solution

Adding to the snapshot strategy jinja handling of the exclude cols config.

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