Add mosapi client to intract with ICANN's monitoring system (#2892)

* Add mosapi client to intract with ICANN's monitoring system

This change introduces a comprehensive client to interact with ICANN's Monitoring System API (MoSAPI). This provides direct, automated access to critical registry health and compliance data, moving Nomulus towards a more proactive monitoring posture.

A core, stateless MosApiClient that manages communication and authentication with the MoSAPI service using TLS client certificates.

* Resolve review feedback & upgrade to OkHttp3 client

This commit addresses and resolves all outstanding review comments, primarily encompassing a shift to OkHttp3, security configuration cleanup, and general code improvements.

* **Review:** Addressed and resolved all pending review comments.
* **Feature:** Switched the underlying HTTP client implementation to [OkHttp3](https://square.github.io/okhttp/).
* **Configuration:** Consolidated TLS Certificates-related configuration into the dedicated configuration area.
* **Cleanup:** Removed unused components (`HttpUtils` and `HttpModule`) and performed general code cleanup.
* **Quality:** Improved exception handling logic for better robustness.

* Refactor and fix Mosapi exception handling

Addresses code review feedback and resulting test failures.

- Flattens package structure by moving MosApiException and its test.
- Corrects exception handling to ensure MosApiAuthorizationException
  propagates correctly, before the general exception handler.
- Adds a default case to the MosApiException factory for robustness.
- Uses lowercase for placeholder TLDs in default-config.yaml.

* Refactor and improve Mosapi client implementation

Simplifying URL validation with Guava
Preconditions and refining exception handling to use `Throwables`.

* Refactor precondition checks using project specific utility

jetty/kubernetes/gateway/nomulus-route-backend.yaml

@@ -26,6 +26,9 @@ spec:
     - path:
         type: PathPrefix
         value: /_dr/loadtest
+    - path:
+        type: PathPrefix
+        value: /_dr/mosapi
     backendRefs:
     - group: net.gke.io
       kind: ServiceImport
@@ -62,6 +65,12 @@ spec:
       headers:
       - name: "canary"
         value: "true"
+    - path:
+        type: PathPrefix
+        value: /_dr/mosapi
+      headers:
+      - name: "canary"
+        value: "true"
     backendRefs:
     - group: net.gke.io
       kind: ServiceImport