Client certificate upport

[bluewalk]

Guidelines

• I have searched the issue tracker and I haven't found feature request like this

Type

Improvement to existing feature

Describe the feature

Background
I am running my own private Invidious instance which is exposed to the internet and protected by a client certificate.
The client certificate is installed in iOS and browsing to my instance it uses the certificate and I can use Invidious.

Yattee doesn't use this certificate (not sure if it can at all) thus resulting in a timeout/error when using Yattee outside of my network.

Feature request
Have Yattee use the client certificate available in iOS (if possible) or have a way to specify the client certificate when adding the location/instance.

[stonerl]

@bluewalk I'm trying to implement a feature where such certificate errors can be ignored. But it might take some time to implement.

See here: #579

[bluewalk]

@stonerl I have seen your PR indeed but it seems to be about self signed certificates, not client certificates. It would require more work to support client certificates I'm afraid.