refs #5940 moved files into a subfolder framework, added autoloader to remove duplicated code to load autoload.php and to be able to register more autoloaders (eg for test files) on demand. This I got read of many includes that had to be updated all the time and that had to be updated all the time when moving iles

refs #5940 we might stay backwards compatible this way for 2 months. moved some tests from unit to integration and explained when a test is a unit test, an integration test or a system test.

refs #5940 put tests in correct folders, better testsuite names, some tests still fail and I cannot figure out why

Adding new PivotByDimension DataTable filter that can pivot a report by (almost) any dimension. The filter can pivot reports by their subtable dimension and can also pivot by other dimensions (by using segments).

Notes:

- in the UI, only pivoting by subtable is supported
- change to CSV DataTable renderer so column names w/ commas & quotes can appear in text
- change to XML DataTable renderer so column names w/ invalid XML characters can be rendered (bit of an iffy change, XML format needs an overhaul I think)
- includes new config option 'pivot_by_filter_enable_fetch_by_segment'
- includes additions to component metadata classes (ie, Report/Dimension)

Refs #6078, extract factory logic from Report::factory and move to new ComponentFactory utility class and reuse in Dimension to allow creating Dimension instances by human readable string IDs.

Refs #6109 New core metric: nb_users as the count of distinct user ids. Means "Active Users". Displayed in Visitors Overview, in metrics picker, in API response, in Metadata

refs #5820 and more test fixes... they all worked when executed standalone but not when executing the whole suite...

refs #5820 fixes some more classes and looks like reportTest needs to be a database testcase as a random method is calling TaskScheduler which requires a DB