HSEARCH-1427 Create a base template to help implementors of ShardIdentifierProvider (rebased from Sanne's work)
HSEARCH-1427 Letting XXE have its reformatting business (no actual changes)
HSEARCH-1427 JavaDoc improvements; Updating reference guide to discuss template class; Adding myself to author group
HSEARCH-1427 Mention fully qualified class in the docs
HSEARCH-1427 Reformat code to use line width of renderable page