Add BND configuration to log4j-1.2-api

[ppkarwasz]

This PR performs the necessary changes to switch log4j-1.2-api from maven-bundle-plugin to bnd-maven-plugin and generate a matching module descriptor.

OSGi descriptor

The import/exports are:

Import-Package
  com.sun.jdmk.comm                      {resolution:=optional}
  javax.jms                              {version=[1.1,3), resolution:=optional}
  javax.management                       
  javax.xml.parsers                      
  javax.xml.transform                    
  javax.xml.transform.stream             
  org.apache.log4j.helpers               
  org.apache.log4j.or                    
  org.apache.logging.log4j.message       {version=[2.21,3)}
  org.apache.logging.log4j.spi           {version=[2.21,3)}
  org.apache.logging.log4j.status        {version=[2.21,3)}
  org.apache.logging.log4j.util          {version=[2.21,3)}
  org.w3c.dom                            
  org.xml.sax                            

Export-Package
  org.apache.log4j                       {version=2.21.0}
  org.apache.log4j.helpers               {version=2.21.0}
  org.apache.log4j.jmx                   {version=2.21.0}
  org.apache.log4j.or                    {version=2.21.0}
  org.apache.log4j.or.jms                {version=2.21.0}
  org.apache.log4j.pattern               {version=2.21.0}
  org.apache.log4j.rewrite               {version=2.21.0}
  org.apache.log4j.spi                   {version=2.21.0}
  org.apache.log4j.varia                 {version=2.21.0}
  org.apache.log4j.xml                   {version=2.21.0}

Remark: unlike the previous versions log4j-1.2-api version 2.21.0-SNAPSHOT only exports those packages, which were present in Log4j 1.x. This is a breaking change. @rgoers, @garydgregory, what do you think?

Module descriptor

module org.apache.log4j@2.21.0.SNAPSHOT {
  requires java.base;
  requires java.desktop;
  requires transitive java.management;
  requires transitive java.xml;
  requires static javax.jms-api;
  requires transitive org.apache.logging.log4j;
  requires static org.apache.logging.log4j.core;
  exports org.apache.log4j;
  exports org.apache.log4j.helpers;
  exports org.apache.log4j.jmx;
  exports org.apache.log4j.or;
  exports org.apache.log4j.or.jms;
  exports org.apache.log4j.pattern;
  exports org.apache.log4j.rewrite;
  exports org.apache.log4j.spi;
  exports org.apache.log4j.varia;
  exports org.apache.log4j.xml;
  opens org.apache.log4j.builders to
    org.apache.logging.log4j.core;
  opens org.apache.log4j.builders.appender to
    org.apache.logging.log4j.core;
  opens org.apache.log4j.builders.filter to
    org.apache.logging.log4j.core;
  opens org.apache.log4j.builders.layout to
    org.apache.logging.log4j.core;
  opens org.apache.log4j.builders.rewrite to
    org.apache.logging.log4j.core;
  opens org.apache.log4j.builders.rolling to
    org.apache.logging.log4j.core;
  opens org.apache.log4j.config to
    org.apache.logging.log4j.core;
}

[ppkarwasz]

NB, using the JAR generated in the appropriate log4j-api and log4j-core from #1819 I was able to run a JPMS application that:

• uses the Log4j 1.x Logger class to log,
• uses a log4j-properties configuration file.