feat(server): add support for multiple CA certs

[OverOrion]

No description provided.

[MrAnno]

Let's try to contribute this back to upstream.

There are 2 questions I would be interested in, but those are not blockers in any way:

• I have memories that it is possible to create a cert trust chain, and the Windows clients sent the entire chain except for the root CA. In that case, thumbprint check may have to be done on the last cert's issuer, not on the first.

• Listing multiple thumbprints in the enumerate response worked as far as I remember. We discussed that it is no longer the case (or I remember incorrectly), so you populated a hashtable instead. Using the issuer field as key should be good enough?!
  Maybe we could check the exact generated SOUP payload to verify if this list idea works or not.

[MrAnno]

I'd suggest opening an upstream PR, allowing the maintainers/authors to comment on it.
If we don't receive any response within a week, I'd happily merge this in our fork (there won't be compat issues even if we have to change the implementation based on their review).