Hide sensitive information in bug reports

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

The automatically generated issue bug report right now contains the whole backend configuration and preview and publish paths. While I think it's useful to know that those are configured correctly I would suggested that we replace sensitive fields with `******`. If they are necessary to debug they can still be disclosed but with explicit knowledge of the author.

**Describe the solution you'd like**

I would like to start a quick list of fields that come to mind that could contain obvious sensitive information:

- `backend`:
- `repo`
- `api_root`
- `site_domain`
- `base_url`
- `display_url`
- `collections`:
- `preview_path`

**Describe alternatives you've considered**

**Additional context**