Separate sequencers into separate modules in the AS7 kit

We recently (for Alpha5) changed the AS7 kit to move the sequencer JARs (which were intended to be the 'jar-with-dependencies' artifact) into the 'org.modeshape' (slot=main) module. However, this creates other issues, primarily that all of the sequencers' 3rd-party dependencies are exposed to the rest of ModeShape; any clashes in the libraries would cause a problem. Therefore, we need to go back to the Alpha4-style AS7 kit that had a separate module for each sequencer (see the Alpha4 AS7 assembly descriptor and the old sequencer module.xml files).

There are some fixes that need to be done to what we had in Alpah4, however:

• Each sequencer module need to be dependent upon the "javax.jcr" module, the "org.modeshape.jcr.api" module, and a new "org.modeshape.common" module.
• The "org.modeshape" module needs to be dependent upon all of the ModeShape-provided sequencer modules.
• Each sequencer module needs to include all 3rd-party transitive dependencies (that is, all dependencies except those from ModeShape and JCR). That likely means the "fileSet" used in Alpha4's AS7 assembly descriptor will likely need to be replaced with "dependencySet" (with some exclusions).