[TASK] Improve information in show_item.php

Currently the "Info" popup (show_item.php) provides information with raw
data from sys_refindex. A editor will get informations such as actual
table name from the database and a uid - but no real hint to what
records it's all about.

This patch provides information about table (name shown in list module),
field name ( as shown in TCEforms) for both references tables

Screenshots in forge issue

Change-Id: I3c053b261573eae47bc812978e3d9d23e69af2e1
Resolves: #29774
Reviewed-on: http://review.typo3.org/4971
Reviewed-by: Jigal van Hemert
Tested-by: Jigal van Hemert
Reviewed-by: Tolleiv Nietsch
Tested-by: Tolleiv Nietsch
Reviewed-by: Philipp Gampe
Tested-by: Philipp Gampe