JVM Protobuf Updates

[lealobanov]

Description

• Bumped Gradle, Kotlin, and other dependency versions to latest as the current setup is 3+ years old
• Added CICD and signing tasks to build.gradle to use the same flow we currently have setup on JVM SDK
• Added 2 workflows for GH actions to a) manually publish a snapshot and b) manually publish a release to Maven from the master branch

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For contributor use:

• Targeted PR against master branch
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Updated relevant documentation
• Re-reviewed Files changed in the Github PR explorer
• Added appropriate labels