OPENIDM-4229 Fix/add javadoc in maintenance project

OPENIDM-3233 Updates to Archive interface - support list of files and version. * Store digest cache keyed off Path object. * Add support for getting the set of files in the checksum file. * Quiet warnings about missing serial version * Factor out checksum-related code from FileStateChecker. Use composition instead. * Fix file handle leak from opening input streams in the archive, but never closing them. * Necessitated change to Archive interface to instead *do something* with the InputStream, so it could be in charge of also closing it. Usng a doWith() style interface to provide the "work" done on the InputStream.