[FEA] Add a feature to remove Tags from a column in schema

[rvk007]

When we perform Categorify on a Target column, Tags.CATEGORICAL is added to the schem. For an internal project we need to remove this tag and we currently don't have a functionality for this.

We can create the below functionality which updates the schema:

schema[column_name].remove_tag(tag=[Tags.TAG_NAME])

[karlhigley]

If the column is truly no longer categorical, then one option here is tag to the column with Tags.CONTINUOUS (which will remove Tags.CATEGORICAL since no column can be both.)

Is the column subsequently processed by another operator that makes it non-categorical? Is it more that you want to exclude particular columns when selecting by tag?