Allow an administrator to set days before an authority is considered "broken"

[benrfairless]

Is your feature request related to a problem? Please describe.
An authority is considered "broken" when it has no applications with first_date_scraped in the last 14 days.

When we bring in smaller authorities, it is entirely possible that there won't be any applications scraped in 14 days due to the size of the authority.

Describe the solution you'd like
Enable admins to change the default 14 day limit to something smaller or higher.

Describe alternatives you've considered
We could leave this as is, however we then just keep opening and closing issues for no good reason. Making this sort of a change will save us time in not having to investigate issues.

Additional context
Examples:

• Buloke Shire Council planningalerts-scrapers/issues#1254
• Bellingen Shire Council planningalerts-scrapers/issues#1223

[benrfairless]

@ianheggie-oaf would appreciate your advice on this one. How long do you think it would take to build a change like this? Do you think it would be valuable, and should we prioritise it?

I think this is only going to become more of an issue as we add smaller and smaller authorities. No need to build it yet, let's just see how much effort this might take.

[benrfairless]

Another example:

• Burdekin Shire Council planningalerts-scrapers/issues#1183