The host (name or IP address) of the Proxy.
Note: If OIDC adapter needs to use a Proxy to talk with OIDC server (Provider),
then at least the "host" config item must be configured to enable the usage of a Proxy.
Supports the client authentication 'client_secret_jwt' and 'private_key_jwt' methods which involve sending a JWT
token
assertion signed with either a client secret or private key.