chore: remove unused slf4j simpleLogger property

[shoothzj]

Motivation

BookKeeper don't use slf4j simpleLogger anymore. Remove unused property.

[shoothzj]

@dlg99 @eolivelli @hangc0276 @merlimat @nicoloboschi @StevenLuMT @zhaijack PTAL

[lhotari]

@shoothzj @nicoloboschi There's a need to do some revisits. slf4j-simple is used in integration tests. This is where this happens:

bookkeeper/tests/integration-tests-utils/src/main/java/org/apache/bookkeeper/tests/integration/utils/MavenClassLoader.java

Lines 118 to 121 in de5a4f2

	deps.add(MavenDependencies.createDependency("org.slf4j:slf4j-simple:" + slf4jVersion.get(),
	ScopeType.COMPILE, false));
	deps.add(MavenDependencies.createDependency("org.slf4j:jcl-over-slf4j:" + slf4jVersion.get(),
	ScopeType.COMPILE, false));

.

[shoothzj]

@lhotari Thanks. It seems MavenClassLoader will load different versions of bk and unify it to slf4j-simple, but why we need this? Let me check if integrate-tests bookkeeper outputs log well later soon.

[lhotari]

@lhotari Thanks. It seems MavenClassLoader will load different versions of bk and unify it to slf4j-simple, but why we need this? Let me check if integrate-tests bookkeeper outputs log well later soon.

It's needed for logging in integration tests. I guess log4j is avoided because of possible classloader problems.

[lhotari]

Actually this PR seems to be fine. The simpleLogger config previously in tests/integration-tests-base-groovy/pom.xml was only used for tests/integration-tests-base-groovy. I think that the actual tests are in another project, so this config was anyways not used.