[FEATURE] Allow custom record list in element browser

Introduces a class variable and a setter for a custom record list
instance in the element browser that can be used to override the
default element browser recordlist.

Resolves: #49037
Releases: 6.2
Change-Id: I41fd3a33f70e72aedef9362ee6bf67de9dcde8ac
Reviewed-on: https://review.typo3.org/21347
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters
Reviewed-by: Philipp Gampe
Reviewed-by: Georg Ringer
Tested-by: Georg Ringer