Config should allow using a separate client cert for mTLS #300
Description
Currently, the operator TLS support only sets the server auth cert env vars, e.g.
SOLR_SSL_KEY_STORE
SOLR_SSL_KEY_STORE_PASSWORD
SOLR_SSL_TRUST_STORE
SOLR_SSL_TRUST_STORE_PASSWORD
For mTLS, users may want to configure a separate keystore / truststore for a separate client cert using:
SOLR_SSL_CLIENT_KEY_STORE=
SOLR_SSL_CLIENT_KEY_STORE_PASSWORD=
SOLR_SSL_CLIENT_TRUST_STORE=
SOLR_SSL_CLIENT_TRUST_STORE_PASSWORD=