Allow Segments to define multiple SQL columns if the segment value can be matched in any of those fields, and use to define two new segments: customVariableName & customVariableValue.

Adding System test case that showcases the bug: ecommerce report with segment "Page URL" shows 0 data

Refactor API.getSegmentsMetadata and Plugin\Segment so segments are all defined through Plugin\Segment class in dimensions & make sure AutoSuggestAPITest data providers do not use database.

Update misc/log-analytics repo for https://github.com/piwik/piwik-log-analytics/issues/67 and update expected test output.

Add expanded query param to DocumentationGenerator so the API test generation logic will not erase the param from API tests.

Make userId segment work for all operators (Is, is not, contains, does not contain, is null, is not null)
fixes #8062
this reverts https://github.com/piwik/piwik/commit/252798d2d742cae998a1f42f50a5ba37c98069df