Create OT&E entities directly, instead of calling sub-commands

This is in preparation for having a web-console endpoint to create OTE.

In addition - we streamline the code:

- we remove support for different premium lists
- we remove support for different DNS writers - we never want a "real" DnsWriter for OTE
- we remove support of --eap_only, because we don't need it anymore
- We use a single password for all the Registrars

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=225841694

java/google/registry/model/registrar/Registrar.java

@@ -19,6 +19,7 @@ import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Strings.emptyToNull;
 import static com.google.common.base.Strings.nullToEmpty;
 import static com.google.common.collect.ImmutableMap.toImmutableMap;
+import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static com.google.common.collect.ImmutableSortedMap.toImmutableSortedMap;
 import static com.google.common.collect.ImmutableSortedSet.toImmutableSortedSet;
 import static com.google.common.collect.Ordering.natural;
@@ -68,6 +69,7 @@ import google.registry.model.UpdateAutoTimestamp;
 import google.registry.model.annotations.ReportedOn;
 import google.registry.model.common.EntityGroupRoot;
 import google.registry.model.registrar.Registrar.BillingAccountEntry.CurrencyMapper;
+import google.registry.model.registry.Registry;
 import google.registry.util.CidrAddressBlock;
 import google.registry.util.NonFinalForTesting;
 import java.security.MessageDigest;
@@ -704,6 +706,28 @@ public class Registrar extends ImmutableObject implements Buildable, Jsonifiable
       return this;
     }
 
+    /**
+     * Same as {@link #setAllowedTlds}, but doesn't use the cache to check if the TLDs exist.
+     *
+     * <p>This should be used if the TLD we want to set is persisted in the same transaction -
+     * meaning its existence can't be cached before we need to save the Registrar.
+     *
+     * <p>We can still only set the allowedTld AFTER we saved the Registry entity. Make sure to call
+     * {@code .now()} when saving the Registry entity to make sure it's actually saved before trying
+     * to set the allowed TLDs.
+     */
+    public Builder setAllowedTldsUncached(Set<String> allowedTlds) {
+      ImmutableSet<Key<Registry>> newTldKeys =
+          Sets.difference(allowedTlds, getInstance().getAllowedTlds()).stream()
+              .map(tld -> Key.create(getCrossTldKey(), Registry.class, tld))
+              .collect(toImmutableSet());
+      Set<Key<Registry>> missingTldKeys =
+          Sets.difference(newTldKeys, ofy().load().keys(newTldKeys).keySet());
+      checkArgument(missingTldKeys.isEmpty(), "Trying to set nonexisting TLDs: %s", missingTldKeys);
+      getInstance().allowedTlds = ImmutableSortedSet.copyOf(allowedTlds);
+      return this;
+    }
+
     public Builder setClientCertificate(String clientCertificate, DateTime now) {
       clientCertificate = emptyToNull(clientCertificate);
       String clientCertificateHash = calculateHash(clientCertificate);