Respect certificate validity period (#391)

Client SSL handler already performs the necessary validation. Only tests are
added.

Server SSL handler does not currently check for the validity period of
the client certificate as the insecure trust manager is used. This PR
added the check but does not actually terminate the connection yet. It
will log the expired certificates so that we can contact the registrars
to update them.

Once we are certain that all certificates are updated, we can turn off
dryrun mode.

We should also consider checking if the certificate has too long a
validity period as it defeats the purpose of using regularly updated
certificates to deprecate insecure cipher suites.

proxy/src/main/java/google/registry/proxy/EppProtocolModule.java

@@ -162,7 +162,8 @@ public final class EppProtocolModule {
       SslProvider sslProvider,
       Supplier<PrivateKey> privateKeySupplier,
       Supplier<ImmutableList<X509Certificate>> certificatesSupplier) {
-    return new SslServerInitializer<>(true, sslProvider, privateKeySupplier, certificatesSupplier);
+    return new SslServerInitializer<>(
+        true, false, sslProvider, privateKeySupplier, certificatesSupplier);
   }
 
   @Provides

proxy/src/main/java/google/registry/proxy/WebWhoisProtocolsModule.java

@@ -134,6 +134,7 @@ public final class WebWhoisProtocolsModule {
       SslProvider sslProvider,
       Supplier<PrivateKey> privateKeySupplier,
       Supplier<ImmutableList<X509Certificate>> certificatesSupplier) {
-    return new SslServerInitializer<>(false, sslProvider, privateKeySupplier, certificatesSupplier);
+    return new SslServerInitializer<>(
+        false, false, sslProvider, privateKeySupplier, certificatesSupplier);
   }
 }