Revert "Replace deprecated AphrontView::setUser()/getUser() calls with setViewer()/getViewer()"
Summary:
This reverts commit 0495b1acf85bfae5fad46f8d944097451422cda2.
Commit triggers a `PhutilInvalidStateException`: `Call setViewer() before calling getViewer()!` in numerous places.
Test Plan: Visit random pages, e.g. Dashboards or Differential.
Reviewers: O1 Blessed Committers, mainframe98
Reviewed By: O1 Blessed Committers, mainframe98
Subscribers: mainframe98, tobiaswiese, valerio.bozzolan, Matthew, Cigaryno
Differential Revision: https://we.phorge.it/D26493