[UWS] Add 3 job destruction policies: ALWAYS_DELETE (default), ARCHIVE_ON_DATE

and ALWAYS_ARCHIVE.

When archiving a job, its former phase is stored in jobInfo under the name
'oldPhase' if no jobInfo is already set.

Archiving a job means that all input files and results are destroyed ; the
error summary and jobInfo (even if it is a file) are kept.

Each archive operation ends with a log message ; in ERROR if failed or in
INFO if successful.

This commit also includes the following things:

    - reformat on 80 characters width the Javadoc of all modified classes

	- fix a bug with the phase transitions: since it is not possible any more
	  to go from PENDING to EXECUTING directly, UWSJob.start(...) must first
	  ensure to be on QUEUED phase. This bug has also been fixed in TAPJob.
	  Similarly, before going into ARCHIVED phase the job must be set into
	  ABORTED phase if not already in a final phase.