[FEATURE]: Advanced Settings Addition: HTTP Basic Auth

Hey there,
I decided to switch to Checkmate recently and am now creating a bunch of Feature request of stuff I'm missing/liked to have.

Is your feature request related to a problem? Please describe.
I'd love to have a HTTP Basic Auth implementation on the Checks. It's hopefully fairly simple to implement.
Extremely useful when services are behind an extra auth layer that is not dependent in activity from the actual service.

Describe the solution you'd like
Having an extendable option in the Advanced Settings where you can Specify a HTTP Basic Auth Username and Password that the check uses when checking.

Additional context
I was trying to implement it myself but I'm not familiar with REACT and your system so help would be appreciated.

Thanks for your help and feel free to take a look at my other Issues!
#3032, #3034, #3035

Start by locating the Checks implementation and the Advanced Settings React entry point, since no specific files or tests are named. Trace how advanced settings reach a check, then confirm how credentials should be stored and applied. Done means a check can optionally use the configured HTTP Basic Auth username and password without affecting checks that leave it unset.

Written by the indexing model from the issue text.