build: migrate logger to SLF4J APIs + Logback backend

[NiccoMlt]

• migrate java.util.logging usages to SLF4J
• drop Apache Commons Logging dependency
• add Apache Commons Logging to SLF4J adapter because of other dependencies
• drop JUL backend for SLF4J
• add Logback as backend for SLF4J

The logger doesn't need the logging.properties file anymore.
The configuration logging.debug.enabled was dropped; just configure the log level in the logback.xml file instead

[hamadodene]

Thanks @NiccoMlt ... Look good to me...
Please add also a note in the README or in another place for migration from logger to SL4J when user will install this PR.

[NiccoMlt]

I don't think that documenting it in the README would be useful, as the logger is an implementation detail that we already are not talking about.

I think we should document it in the changelog when we release it.

What do you think?

[hamadodene]

I don't think that documenting it in the README would be useful, as the logger is an implementation detail that we already are not talking about.

I think we should document it in the changelog when we release it.

What do you think?

Make sense...thanks

[NiccoMlt]

To reduce the chance of merge conflicts, consider integrating this after #515 and before #516

[dmercuriali]

@NiccoMlt +1 but a rebase is needed

[NiccoMlt]

@dmercuriali thanks, I'll do it later this afternoon

[NiccoMlt]

@dmercuriali gave a +1 to the PR yesterday, @hamadodene approved the PR today after the rebase, and the CI passed, so I'm merging it to unlock #516 and hopefully #512