Add an `exclude_tags` Project Variable

[clayms]

Is your feature request related to a problem? Please describe.
I can't explicitly exclude datasets from getting scanned.

Describe the solution you'd like
I see we can use limit_to_tags to limit the scan to only datasets with a particular tag.
I want to use a exclude_tags to the optional Project Variables to explicitly exclude datasets from getting scanned.

Describe alternatives you've considered
Tag all datasets I want scanned with a tag and put that tag in the limit_to_tags Project Variable.
This is unnecessarily tedious when all I want to do is exclude a small number of datasets from a very large number of datasets.

[rymoore]

Hi @clayms - thanks for the suggestion, we'll definitely look into this. Just as a clarification, the "limit_to_tags" feature current only limits the scan by the project tag, not the dataset tag. We felt that skipping over datasets within projects might cause unintended consequences with the lineage so that feature might be out a bit in the future.