Add "pubapi" App Engine service for check API, WHOIS, and RDAP

The migration plan is as follows:
1. This CL, which adds the new "pubapi" service that serves the check API, WHOIS, and RDAP.
2a. Update our public facing sites to switch over to use the new service.
2b. (either order) Rewrite the check API to remove dependencies on flows.
3. ... eventually, once the frontend service is no longer being hit by this traffic, remove its handling of these public endpoints.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=197716346

java/google/registry/BUILD

@@ -40,6 +40,7 @@ registry_ear_file(
     },
     wars = {
         "registry_default.war": "default",
+        "registry_pubapi.war": "pubapi",
         "registry_backend.war": "backend",
         "registry_tools.war": "tools",
     },
@@ -57,6 +58,7 @@ registry_ear_file(
     },
     wars = {
         "registry_default_nocron.war": "default",
+        "registry_pubapi.war": "pubapi",
         "registry_backend.war": "backend",
         "registry_tools.war": "tools",
     },
@@ -93,6 +95,27 @@ zip_file(
     deps = [":registry_default_war"],
 )
 
+zip_file(
+    name = "registry_pubapi_war",
+    srcs = [
+        "env/common/pubapi/WEB-INF/dos.xml",
+        "env/common/pubapi/WEB-INF/logging.properties",
+        "env/common/pubapi/WEB-INF/web.xml",
+        "env/production/pubapi/WEB-INF/appengine-web.xml",
+        "//java/google/registry/module/pubapi:pubapi_jar_deploy.jar",
+    ],
+    out = "registry_pubapi.war",
+    mappings = {
+        "domain_registry/java/google/registry/env/common/pubapi": "",
+        "domain_registry/java/google/registry/env/production/pubapi": "",
+        "domain_registry/java/google/registry/module/pubapi": "WEB-INF/lib",
+    },
+    deps = [
+        ":common_war",
+        "//java/google/registry/ui:war_debug",
+    ],
+)
+
 zip_file(
     name = "registry_backend_war",
     srcs = [
@@ -148,6 +171,7 @@ registry_ear_file(
     },
     wars = {
         "registry_default_sandbox.war": "default",
+        "registry_pubapi_sandbox.war": "pubapi",
         "registry_backend_sandbox.war": "backend",
         "registry_tools_sandbox.war": "tools",
     },
@@ -166,6 +190,18 @@ zip_file(
     deps = [":registry_default_war"],
 )
 
+zip_file(
+    name = "registry_pubapi_sandbox_war",
+    srcs = [
+        "env/sandbox/pubapi/WEB-INF/appengine-web.xml",
+    ],
+    out = "registry_pubapi_sandbox.war",
+    mappings = {
+        "domain_registry/java/google/registry/env/sandbox/pubapi": "",
+    },
+    deps = [":registry_pubapi_war"],
+)
+
 zip_file(
     name = "registry_backend_sandbox_war",
     srcs = [
@@ -204,6 +240,7 @@ registry_ear_file(
     },
     wars = {
         "registry_default_alpha.war": "default",
+        "registry_pubapi_alpha.war": "pubapi",
         "registry_backend_alpha.war": "backend",
         "registry_tools_alpha.war": "tools",
     },
@@ -224,6 +261,7 @@ registry_ear_file(
     },
     wars = {
         "registry_default_alpha_nocron.war": "default",
+        "registry_pubapi_alpha.war": "pubapi",
         "registry_backend_alpha.war": "backend",
         "registry_tools_alpha.war": "tools",
     },
@@ -249,6 +287,18 @@ zip_file(
     deps = [":registry_default_alpha_war"],
 )
 
+zip_file(
+    name = "registry_pubapi_alpha_war",
+    srcs = [
+        "env/alpha/pubapi/WEB-INF/appengine-web.xml",
+    ],
+    out = "registry_pubapi_alpha.war",
+    mappings = {
+        "domain_registry/java/google/registry/env/alpha/pubapi": "",
+    },
+    deps = [":registry_pubapi_war"],
+)
+
 zip_file(
     name = "registry_backend_alpha_war",
     srcs = [
@@ -287,6 +337,7 @@ registry_ear_file(
     },
     wars = {
         "registry_default_crash.war": "default",
+        "registry_pubapi_crash.war": "pubapi",
         "registry_backend_crash.war": "backend",
         "registry_tools_crash.war": "tools",
     },
@@ -307,6 +358,7 @@ registry_ear_file(
     },
     wars = {
         "registry_default_crash_nocron.war": "default",
+        "registry_pubapi_crash.war": "pubapi",
         "registry_backend_crash.war": "backend",
         "registry_tools_crash.war": "tools",
     },
@@ -332,6 +384,18 @@ zip_file(
     deps = [":registry_default_crash_war"],
 )
 
+zip_file(
+    name = "registry_pubapi_crash_war",
+    srcs = [
+        "env/crash/pubapi/WEB-INF/appengine-web.xml",
+    ],
+    out = "registry_pubapi_crash.war",
+    mappings = {
+        "domain_registry/java/google/registry/env/crash/pubapi": "",
+    },
+    deps = [":registry_pubapi_war"],
+)
+
 zip_file(
     name = "registry_backend_crash_war",
     srcs = [
@@ -370,6 +434,7 @@ registry_ear_file(
     },
     wars = {
         "registry_default_local.war": "default",
+        "registry_pubapi_local.war": "pubapi",
         "registry_backend_local.war": "backend",
         "registry_tools_local.war": "tools",
     },
@@ -387,6 +452,18 @@ zip_file(
     deps = [":registry_default_war"],
 )
 
+zip_file(
+    name = "registry_pubapi_local_war",
+    srcs = [
+        "env/local/pubapi/WEB-INF/appengine-web.xml",
+    ],
+    out = "registry_pubapi_local.war",
+    mappings = {
+        "domain_registry/java/google/registry/env/local/pubapi": "",
+    },
+    deps = [":registry_pubapi_war"],
+)
+
 zip_file(
     name = "registry_backend_local_war",
     srcs = [