Merge branch 'hotfix/#6298-#6263-handle-regular-elements-as-target-of-collection-element'

Close #6298
Use constants for events in Zend\Db\TableGateway\Feature\EventFeature
Add an empty newline
fixes cs
#6569 #7066 - minor CS fixes (trailing whitespace, spacing)
Merge branch 'hotfix/#6569-#7066-use-constants-in-zend-db-tablegateway-event-feature'

Close #6569
Close #7066
Merge branch 'hotfix/#6569-#7066-use-constants-in-zend-db-tablegateway-event-feature' into develop

Close #6569
Close #7066
Forward port #6569
Forward port #7066
Fixes Bug #6636: AbstractControllerTestCase fails with multidimensional params array

Added test method testCanHandleMultidimensionalParams to \ZendTest\Test\PHPUnit\Controller\AbstractControllerTestCaseTest that isolates the issue
Fixed the bug by using http_build_query instead of the self-written code to generate the Request-Content
#6636 #6637 - adding `@group` annotations for newly introduced tests
Merge branch 'hotfix/#6636-#6637-abstract-controller-test-case-support-multidimensional-urlencoded-params'

Close #6636
Close #6637
Merge branch 'hotfix/#6636-#6637-abstract-controller-test-case-support-multidimensional-urlencoded-params' into develop

Close #6636
Close #6637
Forward port #6636
Forward port #6637
Removed Exception being thrown when valueOptions property is empty
Removed unrequired test for DomainException being thrown
#6649 #6655 - rendering a multicheckbox without value options should produce an empty string
#6649 #6655 - adding `@group` annotations for newly introduced tests
Merge branch 'hotfix/#6655-#6649-allow-empty-form-element-value-options-in-form-element-renderer'

Close #6655
Close #6649
Merge branch 'hotfix/#6655-#6649-allow-empty-form-element-value-options-in-form-element-renderer' into develop

Close #6655
Close #6649
Forward port #6655
Forward port #6649
Clear up
bugfix unfolding
unit test correction