add enforcer rule for jdk version used in dependencies

[the-other-tim-brown]

What is the purpose of the pull request

Prevents runtime issues where we depend on a dependency that requires a newer version of java to run.

Brief change log

• Add enforcer rule
• Update some execution phases so rules do not slow down compile time and style check runs in test instead of integration-test phase for quicker feedback

Verify this pull request

This pull request is a trivial rework / code cleanup without any test coverage.

[ksumit]

I don't know how frequent such a usecase is but i'm tempted to put <strict>true</strict> as well here. By default it's set to false and could lead to issues? Thoughts?

[the-other-tim-brown]

I'll try it out. It is better to be as "strict" as possible for now :)

[the-other-tim-brown]

This causing lots of breakages: jackson, lombok, log4j all trigger the enforcer rule now

[ksumit]

@the-other-tim-brown should we revive this PR? I used this idea on one of my projects, thanks for exploring these options.

BTW, we can add more specific enforcements to fail the build if lets say they try to build with jdk8. Here are few rules that I'm using at compile phase itself and found them useful:

<bannedDependencies>
    <excludes>
        <exclude>org.slf4j:slf4j-log4j12</exclude>
        <exclude>log4j:log4j</exclude>
    </excludes>
</bannedDependencies>
<dependencyConvergence/>
<requireJavaVersion>
    <version>[${source.java.version},)</version>
    <message>
        At least JDK ${source.java.version} is required to build this project.
    </message>
</requireJavaVersion>