[DS-1456] Make webapp.s register in a new database table when started, so we can
list them later.
Replace kooky URL calculation with fetching it from the configuration.
Reorganize, refactor, implement an alternative MBean approach for trial.
Record 'isUI' in database; add code to 'dspace version' to consume the table.
MXBean approach didn't pan out, so remove (most of) the code.
Remove added context parameters no longer used.
When listing webapp.s, delete records for any not found living.

This sends a HEAD request to the registered URL for the webapp and
assumes that the app is dead if result is not 200.

This change caused a cascade of changes to the treatment of the
database table, because the DBMS layer insists that a table's primary
key be INTEGER.  It was necessary to introduce a new column for the
purpose.  This also means you can have more than one running instance
of the same UI, if you wish.  But it also means that the sequence
required by the new column will overflow after about 2 billion starts.
Declare use of slf4j-api.
Export all collections of a community recursively
See https://jira.duraspace.org/browse/DS-1644

Replace the session variable being queried to determine if a forced redirect to https is needed.
Adds MetadataWebService curation task
Don't emit an EMAIL element if EPerson has a null email
[DS-1667] Remove deprecated LoadDSpaceLNIConfig servlet
Must also deal with null EPerson names when disseminating Groups.
Consolidate all knowledge of whether a session is authenticated into AuthenticationUtil.

Catch all other XMLUI uses of session attribute "dspace.current.user.id"
(which is only set in JSPUI).

Factor testing of "dspace.user.effective" into a new static method to
deduplicate logic and encapsulate the meaning of this session attribute.
Check if an IdentifierProvider supports a specified identifier.
Merge pull request #1 from mwoodiupui/patch-1-mark

Patch 1 amended with changes from Mark Wood
Start JSPUI porting of XMLUI Versioning, create servlet and start jsp
Added i18n message
Mapping servlet, first version of history servlet