Add spotbugs dependencies so we can use @nullable and @nonnull across the codebase

Signed-off-by: Alfredo Gutierrez <alfredo@swirldslabs.com>

Author: AlfredoG87

buildSrc/src/main/kotlin/com.hedera.block.jpms-modules.gradle.kts

@@ -91,4 +91,8 @@ extraJavaModuleInfo {
     module("junit:junit", "junit")
     module("org.mockito:mockito-core", "org.mockito")
     module("org.mockito:mockito-junit-jupiter", "org.mockito.junit.jupiter")
+
+    // spotbugs
+    module("com.github.spotbugs:spotbugs-annotations", "com.github.spotbugs.annotations")
+    module("com.google.code.findbugs:jsr305", "java.annotation") { exportAllPackages() }
 }

server/src/main/java/module-info.java

@@ -7,4 +7,5 @@
     requires io.helidon.config;
     requires io.helidon.webserver.grpc;
     requires io.helidon.webserver;
+    requires static com.github.spotbugs.annotations;
 }

settings.gradle.kts

@@ -37,7 +37,7 @@ dependencyResolutionManagement {
             version("com.google.protobuf", "3.24.0")
             version("io.helidon.webserver.http2", "4.0.10")
             version("io.helidon.webserver.grpc", "4.0.10")
-
+            version("com.github.spotbugs.annotations", "4.7.3")
             // Testing only versions
             version("org.assertj.core", "3.23.1")
             version("org.junit.jupiter.api", "5.10.2")