Platform1: Pass the trusted CA from the OIDC config to the HTTP GET call just like POST

[sbko]

original PR istio-ecosystem/authservice#235

This has been requested by P1

[sergicastro]

I saw this today and started working on it.

Do you the customer needs to specify the same CA for the JWKS get call? or could it just use the config the OIDC is using?

[nacx]

In the original issue, I see they create an additional field for the trusted CA inside the JWKS settings.
I guess it is safe to just use the existing one in the OIDC config? In the end all endpoints should be exposed by the same IdP

[sbko]

I think it can use the existing one. The main problem is that the original authservice doesn't pass the configured CA trust when making HTTP GET calls.
bigbang implemented a workaround for this by setting SSL_CERTFILE env variable pointing to trust bundle https://repo1.dso.mil/big-bang/product/packages/authservice/-/merge_requests/116