ContentIndexParser: ignore_row row type

[geoo89]

Defines a new content index row type ignore_row. For rows of this type, only the column sheet_name is relevant. Ignores/deletes all previous template/flow/campaign/trigger definitions that match [sheet_name] in the following way:

• flow: if exists, any create_flow definition row whose new_name (or sheet_name if not provided) entry is [sheet_name] is ignored
• campaign: if exists, create_campaign whose new_name (or sheet_name if not provided) is [sheet_name] is ignored
• trigger: if exists, create_trigger whose sheet_name is [sheet_name] is ignored

Template definitions are not affected by ignore_row. The rationale is that often, you use a template to bulk-create a bunch of flows (using data sheets) that are auto-renamed to include the data row ID. You may want to avoid creation of these flows, without deleting the template (in order to create flows using the same template but different data).

Fixes #123

[fagiothree]

I don't think we need a functionality to ignore templates and since I have many cases with template_definition and create_flow sharing the same sheet_name, if I understand correctly if I wanted to use ignore_row to ignore the flow creation this would also delete the template definition?

[geoo89]

To reword your use case: The rationale is that often, you use a template to bulk-create a bunch of flows (using data sheets) that are auto-renamed to include the data row ID. You may want to avoid creation of these flows, without deleting the template (in order to create flows using the same template but different data). Is that correct?

I amended the PR so that template definitions are not affected. Please have a look.