Add the ability to migrate to new KBS enclaves.

app/src/main/java/org/thoughtcrime/securesms/KbsEnclave.java

@@ -0,0 +1,49 @@
+package org.thoughtcrime.securesms;
+
+import androidx.annotation.NonNull;
+
+import java.util.Objects;
+
+/**
+ * Used in our {@link BuildConfig} to tie together the various attributes of a KBS instance. This
+ * is sitting in the root directory so it can be accessed by the build config.
+ */
+public final class KbsEnclave {
+
+  private final String enclaveName;
+  private final String serviceId;
+  private final String mrEnclave;
+
+  public KbsEnclave(@NonNull String enclaveName, @NonNull String serviceId, @NonNull String mrEnclave) {
+    this.enclaveName = enclaveName;
+    this.serviceId   = serviceId;
+    this.mrEnclave   = mrEnclave;
+  }
+
+  public @NonNull String getMrEnclave() {
+    return mrEnclave;
+  }
+
+  public @NonNull String getEnclaveName() {
+    return enclaveName;
+  }
+
+  public @NonNull String getServiceId() {
+    return serviceId;
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) return true;
+    if (o == null || getClass() != o.getClass()) return false;
+    KbsEnclave enclave = (KbsEnclave) o;
+    return enclaveName.equals(enclave.enclaveName) &&
+           serviceId.equals(enclave.serviceId)     &&
+           mrEnclave.equals(enclave.mrEnclave);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(enclaveName, serviceId, mrEnclave);
+  }
+}