[FR] Add proactive system check for site_url

[matmair]

Please verify that this feature request has NOT been suggested before.

• [X] I checked and didn't find a similar feature request

Problem statement

Having the wrong site_url set can create hard-to-debug problems (probably https://github.com/inventree/InvenTree/issues/7826). This issue is not actively raised to server admins so it is often lost.

Suggested solution

Add a simple middleware that checks if the currently used domain is:

1. available in the sites
2. the same as site_url if multiple sites are not enabled

• a check for the system status

Describe alternatives you've considered

Add just a system status check

Examples of other systems

No response

Do you want to develop this?

• [X] I want to develop this.