UDFs should be reconfigurable without restarting KSQL

Currently if a UDF needs to be reconfigured/changed it requires a restart of the KSQL server environment. It would be useful if the UDF could reconfigured without restarting the environment which would interrupt running queries.

### Use case
A UDF that uses an embeded in-memory database (like Maxmind) that needs to be refreshed often (daily or more often) would require interruption of the execution environment. In this case reloading the config would restart/interrupt only queries with the UDF in them.

Start by investigating the UDF configuration and lifecycle in the KSQL server environment, focusing on how configuration changes currently trigger a restart. Define the reload behavior so only queries using the changed UDF are interrupted while other running queries continue; the issue names no files or tests to run.

Written by the indexing model from the issue text.