XWIKI-9916: Adding an author and a creator to wiki descriptors and wiki settings documents.
XWIKI-9921: Make new wikis descriptor pages as children of WikiManager.WebHome

Commit done with Eduard MoraruÕs help
[cleanup] Bad merge conflict
XWIKI-9916: Adding an author and a creator to wiki descriptors when they are created.
XWIKI-9708: Repair phase is not executed nor prompted on subwikis when Upgrade All Wikis option is selected from DW
* Add a method to the distribution script service to get the distribution state for a subwiki
* Make the repair UI generic so that it can be reused on the 'Wikis' step
* Add templates/distribution/macros.vm to hold Velocity macros that are shared by multiple steps
* Fix the XAR repair macro in extension.vm as it was working only for the current wiki
XWIKI-9708: Repair phase is not executed nor prompted on subwikis when Upgrade All Wikis option is selected from DW
* * Add templates/distribution/macros.vm to hold Velocity macros that are shared by multiple steps (this time for real)
XWIKI-9624: Authentication is faulty on domain based farm when cookiedomains is set to the exact domain of the main wiki
XWIKI-9909: Concurrent database migration cause SOLR indexer to fail in place of waiting

- fix the race condition fully
- some minor refactoring to increase readability
XWIKI-9720: Use WikiStream by default in XAR import action
XWIKI-9379: Importing a XAR that contains a document called "null" does not work
XWIKI-9479: In multiwiki mode user picker field should automatically look by default for local or global users depending on the multiwiki type
* Improve the group picker following Anca's suggestion (an wiki with global users only can still have local groups to manage the global users).
[misc] Bulletproofing
XWIKI-9922: When attachment author/creator is not provided confluence parser send null author/creator
XWIKI-9923: The generated Table of Contents is empty for the ODT export
* officeExport.xsl was expecting the content directly under xwikimaincontainer DIV, but the content is under xwikicontent DIV.
* remove duplicated code in pdf.vm and make sure the xwikicontent DIV is generated both when a single page is exported and when multiple ones are.
XWIKI-9923: The generated Table of Contents is empty for the ODT export
* Update xpath that matches headings in xhtml2fo.xsl
[misc] Add toString() implementation
XWIKI-9720: Use WikiStream by default in XAR import action
XWIKI-9379: Importing a XAR that contains a document called "null" does not work
Merge branch 'feature-xarimportwikistream'
XWIKI-9847: Distribution Wizard first step does not see empty databases anymore
* Fix the query that counts the documents that are not xclasses so that it works on Oracle. Thanks to Sorin and Denis for catching this.
XWIKI-9782: New Crypto Service API

- Add an internal bouncy castle interface for digest
XWIKI-9927: Error in R40000 migration when name column of statistics table is null