SSL certificate warning on top shows up too early before expiration

### Prerequisites

Please answer the following questions for yourself before submitting an issue. **YOU MAY DELETE THE PREREQUISITES SECTION.**

- [x] I am running the latest version (v0.100.9)
- [x] I checked the documentation and found no answer
- [x] I checked to make sure that this issue has not already been filed

### Problem Description

The SSL certificate expiration warning begins to show up a full month before the certificate was to expire (in my case the 9th of March), which can be pretty problematic when using an ASUSCOMM-administered certificate which only lasts 3 months before they allegedly get renewed upon or very close to expiry.

There's also no way to close the banner, apart from using `##.topline.alert-warning.alert`, which may or may not block other kinds of warnings as well.


### Proposed Solution

Make it possible to adjust the amount of days remaining until expiration before the SSL warning begins to show up.

### Alternatives Considered

Add a close button to the warning(s).

### Additional Information

I wouldn't be surprised if my use of a __________.asuscomm.com SSH certificate as my HTTPS certificate in my AGH settings, would be considered technically questionable. But they're free of charge, are included and very easy to set up in modern ASUS routers, and does not seem to cause any visible breakage apart from not supporting client connections from IPv6 IPs.