Export link in "organisational plans" in `/plans` should list link to all phases

[nicolasfranck]

Please complete the following fields as applicable:

What version of the DMPRoadmap code are you running? (e.g. v2.2.0)

3.1.1

Behaviour:

The list of plans in /plans lists plans with visibility "organisational"; The download link however only allows to download the pdf of the first fase. plan_export_path requires an extra parameter phase_id for that. Add a link for every fase? Or make a submenu from which you can choose the right phase? That way it works similar to the download tab of a plan