Implemented logging for LDAP searches performed by LdapTemplate

[Haarolean]

Hi,

I've implemented some logging for LDAP searches performed within LdapTemplate. Resolves #345.
I believe this will help and greatly improve the experience using spring-ldap, as the issues people (and I personally) encounter usually are hard to debug or investigate.

1. I've extracted some common parts to reduce/prevent code duplications and added logging there;
2. I've spotted some straight-to-fix warnings and some anonymous classes with lambdas, so I took the liberty. These changes can be viewed independently within one of the two commits in this PR. Let me know if these changes are unwanted, and I'll revert.
3. The test run is successful: BUILD SUCCESSFUL in 1m 44s; 67 actionable tasks: 57 executed, 10 up-to-date

Cheers

[Haarolean]

@jzheaux hey, sorry for the ping. Is there anything else I could do here to add some traction to the PR?
I'd even apply for a position at VMware to help out with maintenance stuff but they're not hiring atm :-))

[jzheaux]

@Haarolean, sorry for the delay. I'm taking a look this week.

[jzheaux]

Thanks, @Haarolean! This is now merged into main.

[Haarolean]

@jzheaux thank you!

[ranma2913]

Thanks for adding this. It's going to help out my project right away since I'm working on running native queries.