Add customizer for jOOQ's DefaultConfiguration

[snicoll]

jOOQ has a number of "provider" interface one can implement to tune its behaviour. We've started to look for beans of such type to automatically customise the DefaultConfiguration jOOQ is using.

Over the years, an increasing number of callback interfaces have been added which makes our auto-configuration a bit verbose. Also, it is unclear if those implementations have to be bean in the first place. It feels like they are registered as beans for the sole purpose of being found by the auto-configuration.

Given the current arrangement, we've decided to provide a customizer and let users tune the configuration going forward.

[snicoll]

This is noteworthy as checking for the presence of the following beans is now deprecated:

• ConnectionProvider
• ExecutorProvider
• TransactionProvider
• RecordMapperProvider
• RecordUnmapperProvider
• Settings
• RecordListenerProvider
• ExecuteListenerProvider
• VisitListenerProvider
• TransactionListenerProvider

Users relying on this behaviour can restore the configuration by registering a DefaultConfigurationCustomizer bean that customize the DefaultConfiguration. Note that the underlying provider(s) no longer need to be registered as a bean.