[FEATURE] Add option to ignore "entire content gone" as a change

[DL6ER]

Is your feature request related to a problem? Please describe.

I recently added

name: "Stadt Erftstadt: Neuigkeiten"
url: "https://www.erftstadt.de"
ignore_connection_errors: true
filter:
  - css:
      selector: div.SP-Search:nth-child(1) > div:nth-child(1)
      exclude: img, dt
  - html2text: pyhtml2text
  - strip

It reliably sends me an email on 04:00 UTC that all the content is gone only to report at 04:15 UTC that everything is back. This is repeating on 4 out of 5 days I have added this to my jobs.

I realized this while testing the fix for #104 so both may or not (!) be related with that fix. It did not happen yesterday when I experimentally downgraded to v3.30.0 but this also might have been coincidence.

Describe the solution you'd like.
An option to ignore such "the entire content is gone" errors much like we already have the ignore_connection_errors: true. I suggested this initially here: #104 (comment)

Describe alternatives you've considered.

Unclear if there are any viable alternatives

Additional context.

Mail on 04:00 UTC:

Mail on the next check (happening 15min later at 04:15 UTC):

[github-actions]

🤖 Hi @DL6ER, I've received your request, and I'm working on it now! You can track my progress in the logs for more details.

[github-actions]

🤖 I'm sorry @DL6ER, but I was unable to process your request. Please see the logs for more details.

[mborsetti]

Hi @DL6ER,

Good suggestion. Will look into developing it!