[BUGFIX] Select suitable distribution version in em

The distribution installer selects current_version=1
extensions only and fails in core v7 since the current
introduction version is not compatible with v7 anymore.

The patch changes version selection a bit to first find
all distribution extensions, then filters those suitable
for given core version, then filters latest version of
the distribution extension.

Installing introduction package in 7.6 works again.

Change-Id: I11f2def2ea606ada5f7c3efd3043f59bd4be0452
Resolves: #81068
Releases: master, 8.7, 7.6
Reviewed-on: https://review.typo3.org/53262


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>