Handle Java source versions other than 8 for compile-jsp

[cherylking]

Fixes #1812

• requires PR Handle Java version above 8 for compileJSPs task ci.ant#171 in order to setSource for versions later than Java 8.

This PR does the minimum necessary to fix the issue:

• Checks for and uses the release parameter for setSource if it is specified in the project maven-compiler-plugin config
• If that is not found, checks for and uses the source parameter for setSource if it is specified in the project maven-compiler-plugin config
• If neither of those are found, check for and use maven.compiler.release Maven property or maven.compiler.source Maven property if specified.
• If neither are found, the Ant task defaults to using the System property java.specification.version
• The ant task will also use javaSourceLevel if the version of Liberty is 24.0.0.1 or later and the value used for source is Java 8 or later. Otherwise, it will still use jdkSourceLevel for older versions of Liberty.

[cherylking]

Doc for reference - versions older than 24.0.0.1 do not document a javaSourceLevel attribute.