[TASK] Add placeholder attribute to password ViewHelper

As a follow-up to I24bb73c5de5a494259171ff289d434892f85e16e,
this also adds the placeholder attribute to the password
ViewHelper.

Change-Id: Ib442a6b1a52f9ddc38a9227311559d8803443eee
Related: #37558
Releases: master, 2.0
Merge "[TASK] Add placeholder attribute to password ViewHelper"