HikariCP 2.4.0 extension module cleanup

[jtduffy]

Description

Since the HikariCP extension module has been migrated into the agent as a proper instrumentation module, the old extension module artifacts need to be cleaned up.

• Remove the hikaricp 2.4.0 extension from the extensions repo: https://source.datanerd.us/java-agent/incubator
• Remove the artifact from the production S3 bucket so it will be removed from the download site HTML the next time the agent is released
• Notify TSEs of the cleanup

[workato-integration[bot]]

https://new-relic.atlassian.net/browse/NR-294781