Add special parameterlist to activity manager

Allows extensions to specify special parameters, eg username (adds avatar) file (moves path to tooltip)

Fixes https://github.com/owncloud/core/pull/12749/files#r21623294 as soon as https://github.com/owncloud/activity/pull/192 has been merged afterwards

@DeepDiver1975 @LukasReschke @schiesbn