Update logging

[DomGarguilo]

This PR updates the logging in this repo.

Things seem to work correctly for the most part although for some reason, only the log.error statements are being printed during the tests. This might be caused by some config issue but I am not sure.

I based these changes off of some of the other repositories dependencies but I am not sure that everything is correct or optimal.

[dlmarion]

We removed SLF4J?

[DomGarguilo]

We removed SLF4J?

Oops, maybe not. I'll add it back.

[DomGarguilo]

We removed SLF4J?

So actually the slf4j dependencies where removed from the pom because the log4j-slf4j2-impl provides an slf4j "provider". If the org.slf4j dependencies are present, a warning is thrown.

[EdColeman]

In the main accumulo pom - log4j-slf4j2-impl is declared as unused dependency. For proxy, would runtime or provided scope be more appropriate and resolve the build error? The real dependency is slf4j - the implementation(s) provided by log4j2 could also be satisfied with logback (I think, it has been I while since I have used that instead of log4j2) so is the -impl is transient and needs to be provided at runtime (and for tests?) but that is a runtime detail and not a dependency in maven build terms.

[ctubbsii]

Superseded by my fix to logging in 7bcf98a