Feat: Update to JDK 17 and Jakarta Namespace

[tanya732]

Changes

1. Modernizes the build toolchain and migrates to the Jakarta Servlet namespace, establishing Java 17 as the minimum supported version.

2. Built on top of the community contribution in Updated to JDK 21, gradle 8, fixed tests #156 by @TareqK, adjusted to use Java 17 as the baseline.

3. Build Toolchain

• Upgraded Gradle from 6.9.2 → 8.10
• Set Java 17 as the minimum language version (source, target, and toolchain)
• Removed japicmp binary compatibility plugin (incompatible with Gradle 8.x)
• Removed Guava JVM environment workaround (no longer needed with Gradle 8)
• Updated JaCoCo DSL (xml.enabled → xml.required) for Gradle 8 compatibility

4. Jakarta Servlet Migration

• Replaced javax.servlet:javax.servlet-api:3.1.0 with jakarta.servlet:jakarta.servlet-api:6.0.0
• Migrated all javax.servlet.* imports to jakarta.servlet.* across all source and test files

📢 Breaking Changes

• Minimum Java version raised from 8 to 17
• Servlet namespace changed from javax.servlet to jakarta.servlet, applications must run on a Jakarta EE 9+ compatible servlet container (e.g., Tomcat 10+, Jetty 12+)